I would suggest, until you can get a new machine, that you just leave it on all the time. I may be wrong (correct me if I am Cabe) but I don't think they really use that much power when they're in sleep mode and I don't think it's very harmful.
I used to leave my desktop on all the time, I think at one point I left it on for like five months straight and it's still running like a champ.
