Welcome from NJ. Sorry, don't know of any Philly groups. I do know of a group that meets here locally (about 45 min. north of Phila.) but I think it's monthly. Not sure they are particularly a 'charity' group, though. Just a group of quilters that work on their own projects at the library as far as I know. About the best suggestion I could give you, check w/my LQS, Pennington Quilt Works
http://penningtonquilts.com and see if anyone there has some hints/clues for you. There is also
http://thelittleshopforquilting.com in Haddonfield, NJ. (Just across the river from you). They might be able to give you some info as well. They have a very nice shop and the gals are very helpful.