Help Help anyone!

My worst nightmare has come true.  I have a 90' Vanagon GL with 140,000
miles and a blown head gasket in Los Angeles.

Estimated costs of repair are in the thousands!  I was thinking of doing a
GTI conversion, but just learned that the only company in CA in Gilroy,
stopped doing them last year due to lack of parts.

Does anyone know of another place I can do a conversion in Southern
California?  Is a subaru engine conversion reliable?
Is my best option to replace the engine with a rebuilt, due to the high
mileage?
Where can I take my car to have the work done in Southern CA for a
reasonable price?
Should I sell the van (otherwise in good condition)?

Please help!

Thanks!