WAN via dedicated line/Internet via DSL

The local Boy Scouts of America have 3 Windows 2000 and 2 Windows XP computers. Two of the PC’s have static IP addresses and are connected directly to BSofA headquarters WAN in Texas by a 56K frame connection and the other 3 PC’s are connected to a BellSouth DSL router using DHCP. They would like to have all 5 PC’s share the DSL connection AND connect to the BSofA headquarters WAN. They have ZERO funds budgeted for this! Any ideas or recommendations?