peer to peer perform prob’s 98/Me/2000 p

I have a new cilent who has approx 25 PC’s with a mix of 98, Me and 2000Pro, two Cable Modems and a 98PC operating as a peer-to-peer server for a small work group. This work group is having performance probs, SW house suggests a dedicated 2000 server and all 10 PC upgraded to 2000Pro. This is not a problem with time, does any one have any short term answers please !!!!!