Before you go buying a T1 card, I would advise you speak to whoever your MPLS provider is. I am currently working with Etisalat and they are providing a managed router on site and giving me an Ethernet presentation to my router. With a CE managed router this is quite normal. You can then use shaping on the interface to make sure you don't oversubscribe it. If they are giving you V.35 presentation then you need a serial interface, such as a WIC-1T.
Your MPLS provider is asking how you are going to propagate routes between sites. If you currently use static routes most MPLS providers can support this. However if you use EIGRP you will have to look at either migrating your network, or performing redistribution in and out of the MPLS network. You will need to tell them the address space you are using and your routing protocol.
And yes, you could use the same type of router at each location; it will also make support easier.
