I have a 70 Chevelle, 350 with luke-warm AC at best. I am GUESSING that the refridgerant is low. Is there anything else that could cause cool, not cold, air? Also, due to the new laws about freon, what would a likely cost be to have the refridgerant filled. Thanks in advance...

There could be several other components that could cause your problem. Go to a qualified repair facility for a recharge, if when recharging the system they discover another problem, they will advise you if you request. If it turns out to be nothing more than a recharge, price will be around $85 to $100. R-12 this year is about $50.00 lb.