You can buy a new air handler. And have it installed. It will have to be an R-22 unit. Depending on if you can get the unit out of the attic.. it can be worth it, or not.
A 3 ton split system is 1650 delivered. You can get someone out to evacuate your old system. Then if you can cut the line-set close to the unit, and place the new ones. That way all the AC guy has to do the braise the lines and hook it up.
If you are in a house that put the AC in the attic with no exit... Hopefully you have asphalt shingles, you will have to go out the top. This is a LOT of work. But can be done. When my parents replace their air handler... they will have to cut a hole in the ceiling in the garage and lower it down.
Link to $1650 system,
http://www.ebay.com/itm/111276007746If you get it all set up, then there is no reason that the AC tech should charge a ridiculous amount.
30lb of R22 is about $300 on Amazon. $10 a pound. You can buy by sending a message to the seller that a certified tech will install it.
http://www.amazon.com/R22-Refrigerant-30-Disposable-Tank/dp/B00F06NDS0/