2 x Cisco 1721’s linking 2 sites

Hi,
I have about 4 sites that all run on the IP range of 172.20.x.x / 255.255.0.0
I’ve been chalenged with linking the main site with one of the remote sites. We have just had a BT Megastream installed, UK eqivilent of a T1 i beleive.
I have done a CCNA, but i’m very rusty on the subject,so i’m using config maker. I need to use the following IP addresses to link the sites, how do i go about this as i’ve tried subnetting and the networks won’t communicate.

Site A: 172.20.2.77 / 255.255.0.0
Site B: 172.20.30.30 / 255.255.0.0

Help!!

Thanks

Adam