Not sure where you are in Tx, but there are some good aftermarket A/C systems produced in the great state of Texas. If you are in East Texas, I'd recommend using a kit that ties into the defroster (all three of the companies below offer this). Kit pricing is on the web sites.
Not in any specific order:
Old Air Products:
http://www.oldairproducts.com/catalog/contact_us.php
Classic Auto Air:
http://www.classicautoair.com/contact-us.html
Vintage Air:
http://www.vintageair.com/contact.asp
If you are interested in reading about what it takes to install one, there is a brief write up on the Classic Auto Air "Perfect fit" kit on the web site in the signature below.
Good luck!