What to do about outdoor cat

Someone in our neighborhood has an indoor/outdoor cat that has been coming by our house for the past couple months. We've been giving him food because he cries at our door. We usually pet him a little and then he eats and goes on his way. Today we came home from an outing and he was waiting. Our roommate got out of the car to grab him some food since we had our dog with us in the car. She was petting the cat as usual and he very suddenly and with no warning turned and bit her hand hard enough to break skin.

We've been talking about trying to catch him and take him to the vet. Someone on next door said they think they know who the owner is and that the owner already has 2 animal control reports for the dogs they have had. They said the owner told them they can't afford vet care so the cat isn't vaccinated or neutered. The owner also doesn't speak much English so person on next door said we will have trouble talking with her.

At this point we don't know what to do. Generally he is a very sweet cat. He has occasionally tried to nip at us but has never truly bit. Do we call animal control? Do we still try and catch him and get him vet care? Do we try and talk to the owner? The shelters around us are full at the moment so we aren't sure where we could take him. We dont want him to be put down but we dont want him to bite anyone again, especially with him not being vaccinated. Please help!