Fix this right away, change the batteries and get a remote battery holder. Battery leakage will do a lot of damage to your boards. Once you get it on the boards, its a cancer that is hard to get rid of. As for cost of having it fixed there is a post on pinside somewhere where some techs posted what they charge per hour. If I recall correctly the average was around $75 for in home service and $45 if you take it to them. But you should learn to do a lot of that stuff yourself. Go to pinwiki.com and read up on how to repair your machine. It will save you a lot of money and isn't very hard if your a little mechanically inclined. And you will have the support of pinside if you get stuck on how to do something.