It sounds like you just need your derailers adjusted. You can Google for some help on how to do this yourself or maybe your boss will help you out. Sometimes the LBS will do this for $10-15, but I think alot of them charge more than that. Of course in your area you have other low cost options as well like the bike kitchens etc. There someone would teach you what you need to do. If you are mechanically inclined at all its not that difficult to figure it out yourself IMO.