2 isp in a 22 stations(pc’s to be connected)

i have a small cafe in our hometown. but the maximum speed that this isp can give is only 1
.5mbps. i have 22 pc’s sharing in this one same network. i requested to upgrade the speed hence accdg to them cant offer higher than 1.5..so i requested instead for another connection..another 1.5 acc to have 2dsl line. my problem is i cant set-up just one network..1 have 2 routers and 2 12port switches…thanks