Check with your local school, they should have programs available or know of available programs. Also check with the local Department of Human Services as they can often point you to programs in your area that are free to low income families.
My son has ADHD and my daughter and myself have ADD....always a struggle. Both my kids are very social but with my son, his problem was in the kids he choose to hang around with (kids who get into trouble). The school has a program called AEA that brought in a therapist to see him at school once a week. The school had a program to help kids who weren't making good choices but hadn't been in trouble as yet...both of these things helped my son quite a bit though he wasn't happy about doing them at first (they are both free programs) as he was embarrassed to be in a group of his peers but once he got in there and found that these kids had much the same problems, he settled down and did very well.
Our local town had a program for kids his age that I also got him involved in (it was free to us as we are low income as well) that helped him work on his social skills and decision making skills (he choose the one on one rather than the group tho it was available to him). As I said, he wasn't happy about any of it, but once he got involved and tried what they suggested, he found that it helped him quite a bit.
AEA (Area Education Assistance) is a Federal/Nation wide program offered everywhere but I've found that schools will not tell people about it, you must ask but it is always free (they don't like putting out the money for it as it is the schools responsibility to pay/provide it). Working with them is great, but be forwarned, you will have to meet with them and his teachers to find out exactly what he needs help with at school and work together with them to figure out what will work best for him...it's a trial and error thing, but once everyone figures out what works best for your son, that is what everyone will continue to do to help him.
My son has sensory issues that needing tending to and the school, with AEA's involvement, set it up so that he can go to the gym after every other class and play basketball and run around (leaving class two min. early and arriving at the next one two min. late) as it helped him work out some energy that had built up so that he could pay attention in class better. When a teacher is available to assist him, he gets to go into the weight room and work out. They also provided therabands for him to work out with as well (when his asthma is acting up, it's a quiet activity but helps him to burn off energy). This has helped him quite a bit and his grades improved and with the assistance of the other programs that we found, he is making better decisions as well. I'm sure that they will have programs available to help socialize your son as well. Good luck to ya hun!! :)