You should take a read through this: http://68kmla.org/files/classicmac2.pdf before you operate it further to avoid potentially more extensive damage to repair. The good news is, there is almost nothing that cannot be easily and inexpensively repaired once identified.
Rescuing an old Mac is a lot like rescuing a dog if you've never had one. They need lots of care to nurse them back to health and the purchase of a few unique items you are not in the habit of having around your house. Chief among them is to get yourself a good mutli-meter to help keep your aging Mac in good health as its age will continue to show itself, especially under resumed routine use.
Replacing the RAM chips is fairly easy but you will of course need to pick up replacement donors, the easiest means is via another defective logicboard which turn up from time-to-time on eBay. However these are the original 64 chips, not to be confused with later 256 chips associated with the 512K, which are more common. Others may have a source for the chips themselves. I've read enough comments around the net that bad RAM chips are fairly common in these old Macs due to a condition described as bit-rot, so any donor board will have to be checked for bit-rot as well so you don't replace bad with bad. Installing a socket will speed replacement in the future as well, especially if your chips are untestable prior to installing.