Our next door neighbor recently had our property lines surveyed after living here for 12 years. The property line on the right side of our back yard had been a little fuzzy but didn't really matter until they decided to put in a fence. Turns out, our fence is about 8 feet beyond the property line. She said not to worry about it but we're afraid if either of us wants to sell in the future, of course, it will be then be an issue. We'd like to just purchase the chunk of property that we thought was ours in the first place (I have spoken with the surveyors and we are over too far, not just taking neighbors word).

Our neighbors are open to this but we'd like to do this ourselves without getting too many professionals involved if possible. Do I just need to contact a real estate attorney or what is the best way to go about this without having to pay out too much in additional, perhaps, unnecessary fees?

In order to facilitate what you want and pay for it, you will have to get a surveyor to do the property line and file it with your township and your mortgage company, then go from there. IMO.