1999 Chevy Venture Repairs

Can anybody tell me, what my outlook might be in paying for the following repairs on this "heap of junk", I have owned for only a year?
I have a 199 chevy venture. In less than a year that I have owned it, I have replaced: tires, waterpump, radiator, hoses, head gasket. Now, a year later it has been overheating badly and water is leaking from the radiator. Took it to a shop yesterday and the mechanic told me he refuses to fix it. He said that after throughly checking it, said it needs the head gasket replaced again and that the radiator needs replaced, along with the heating coil. (He would not quote me a price) My final question is: Do you all think I ought to just have the van fixed & be done with it or do you all think after a year, I ought to just sell it for scrap? This van was a gift from my sister a year ago. She paid 9 grand, so far I have put in 3 grand in repairs. My husband wants to just get rid of it. My father-in-law thinks we ought to just repair it. Do you all know if this will be an expensive reapir job?