Brand new crate transmissions go for $1600 before shipping...
You may find it cheaper in the long run to buy a crate model instead of having a wrecker model taken apart and done up.
I will say this to help you... fit it into your budget to have a cooler put into the trans system. Use the fill bolt as the return and pull the feed from the bottom of the pan (drill - tap - screw in fitting). You'll see increased life this way for a fairly cheap mod (shouldn't be more than $150 for a pump, cooler, and lines). If you throw the LSD in there with it you'll see reduced wear on it and better traction feel as well.