Can anyone helo with Back Up Solution?

I need ideas for back up our system in the ofiice. We are a growing company and we are moving to a new office in a month time. We have a server and 8 other computers which half are PC running in windows XP and the other half are Mac running in OS 9. The problems is that we have design files in the mac and databases in PC and i have to make back them up as well as the server frequently. If cost is not too high maybe everynight or at least once a week. So far PC and Mac talk with Appletalk. If anyone can help me would be highly appreciated.