two domain controllers

I inherited a 2 site network that is Windows 2003 servers seperated by 1 1.5mb t1 leased line. they have 2 Domain Controlers and both are in the same location and the 2nd location is hosed if the t1 is down, no one can log in and be authenticated at the 2nd site. they have one domain and use active directory and exchange.

can i setup a dc at the second site with dns and speed up the process? How do I do this?
should i leave the 2nd dc at site 1 alone? or move it to the 2nd site instead of setting up a new server?
Dan

Yes it can be possible but initially you need to remove all the replications from the server.