welcome...
before spending another nickle on the car, inspect the suspension console on the passanger side and the rest of the chassis to insure it is not too badly rusted or damaged...
soda blasting good...sand is bad
depending on your skills the car can be done in the price range, of course you'll shoot to for the lower price but expect to be closer to or over the $8K range (from the looks of your garage, you have and like tools so you are off to a great start)
for the conversion parts, if going with used, be careful of buying piece parts such as the adapter plate or flywheel unless you know for sure what they;ll work with. nothing worse than buying an adapter plate only to find out that it's an old design and its difficult to find the correct flywheel or pressure plate or other stuff...
the more HP you want, the more $$$$ it'll be.....