Im learning as i go here. This is my first admin job.
Ive decided to have a look at ethereal to try and isolate the bottleneck(s).
Ive never used it so doing a lot of cramming on the documentation.
Theres an old 10mbps switch in the closet that i know isnt doing the network any good, so im gonna replace this with a 100mbps switch with a few 1000mbps ports for heavily used servers.
I used a program called netcps and found the transfer rate on the network range from 1-3mbps.

Thanks all for the advice again, priceless!