its probably just your AC pump. not everything is as difficult as it seems. everyone can try to get technical about this, but the fact is, with AC units the most common problems are 1. freon is low. 2. AC pump is bad. 3. electrical problem.
the only one you need to worry about really is if its a electrical problem.
obviously its not Freon. if its the AC pump unit, might i suggest
http://www.car-part.com find the least expensive part there that is close to you. (the further the part the more the shipping will cost)
if you take it into a electrical specific shop the can test your AC unit for a very cheap reasonable price. if it is bad they will tell you what need to be fixed, if it is not bad then your clutch in your AC pump is screwed and the unit need to be replaced.
i hope that helps you better.