Question : New Office Setup

I need some advice and also looking for some possible solutions.  We currently have two offices with following setup:

Los Angeles (San Fernando Valley)-Main Office:
Workgroup with 25 users
2000 Server, SQL Server, and Web Server
Verizon Westel DSL Modem
CISCO PIX 501 Firewall/Router
24 port 3COM Switch
5-Printers, 2-Copiers, 4-Fax (all networked)
With external SCSI sony tape backup

New Jersey (Edgewater)-Branch Office:
Workgroup with 5 users
Windows 2000 Server
Verizon Westel DSL Modem
Linksys Router/Firewall (which is not good in my opinion)
16 port switch provided by Dell (which is bad in my opinion need to relpace it)
1-Printer, 1-Copier, 1-Fax (all Networked)
Need to get a backup device ASAP

We are now looking to setup an office in downtown Los Angeles for 10 new users.  I am planning on to set it up like the New Jersey office except with better switch and router.  Also both offices currently use (share) a project status, an all in one customer service interface on SQL imported from access (designed by me unfortunately).  Running project status from the NJ office is kinda laggy since it has to constantly update it from the CA main office.  Since we do not have an internal instant messaging system we all use Yahoo IM to stay in live communication with one another within each office and between offices. Unfortunately I am the only one in the IT department.
I am pretty much self taught, no formal background in networking or computers (environmental engineer by trade).  
My questions are:  

1)Am I better off continuing to use a workgroup environment or shall I switch over to a domain?
2)Is it a good idea to continue to use Yahoo as our IM service?
3)How do I make all the servers communicate with each other?
4) Is it possible to send print jobs from one office to another i.e. CA to NJ?
5)If I do switch over to a domain would using MS SBS 2003 any good? I heard this is only good for 50 users and I am pretty sure we will grow beyond 50 users by end of this year.
6)Also we have alot of subcontractors that constantly need access to out FTP and that is now taking a toll on our bandwidth and connections.  Any other better suggestions would help on this one.
7)If I switch over to a domain I want to start it with the new LA office.  Would I be able to switch the other two offices over to a domain easily with minimal downtime?
8)Our project status now will be shared with the new LA office would that slow our connection/bandwidth down even more? If so any suggestions with project status is welcomed.  I was thinking about transfering our project status to the web..would that help?
Anyways these are all the question I have for now, I am sure I will think of more.  Any suggestions, answers or help to any of my questions would be greatly appreciated.  

Thank you, Thomas Joh

Answer : New Office Setup

Just some added comments

#1 - I would get your site-to-site VPNs up and running, then do a DCPROMO setup on LA server #1, then on NJ, then on LA server #2.   Once active directory is setup, all of the clients *should* be able to resolve all of the network devices over the the VPNs to the other sites.

#3 -- You could get two more PIX 501s and have a fully meshed VPN without any trouble.  If you can get reliable/fast sDSL that is best for VPNs and site-to-site communications.   I've seen client implementations (with a PIX 515 at hub site and 506 at spoke sites) for 500 users across 12 sites.  I think in your scenario three 501s could handle the traffic/vpn load.

#4 - After you get VPN and active directory, all of your shared network printers (say you share the 5 LA printers on your LA server#1) they show up in active directory for the clients in NJ and LA #2.

#6 - It depends.  Are your contracts sending files from your office to somewhere?  Are they retrieving files they've stored already somewhere?  If they've worked on files and then post them to an web/ftp host, then when they download them to your location that is coming in on the fast side of aDSL.  If they are posting files from your location to somewhere, it is going out the slow side (upload) of your aDSL (assuming aDSL of course).  Tell them to bring a laptop or put the files on a CD-R. :)  -- It might be just as cheap to get a second DSL connection that is just for file transfer use.  Then set up a cheapo linksys router and tell them that if they are transferring files, please make their default gateway the linksys router.  In midsouth, SBC sells aDSL on top of an existing POTS line for $36/per month with 1.5m down/384kup, so I figure similar options about on east/west coast.

#7 - Active directory in a multi-site is a little detailed but I think you'll find it relatively easy to manage.

#9 - Can you convert your application to a web/ASP page?  I'm assuming that you are still using Access as the front end to your SQL database.  If your app was on a web page in LA, I think you would see great speed improvement.