Did water mix with oil? if not somone on here would prolly fix this for a fraction of the "shop" cost.

If water did mix w/oil you could flush it with fresh oil+filter and have somone do the gasket but there'd be no guarantee that there wont still be water/moisture that could cause probs.

Or you can just buy a motorset off here s14 or s13 and put it in or have somone do it for cheap, motorsets are what $250-$500(This is what I would do if water mixed w/oil)

I wouldnt sell a car over a blown headgasket, not one of these at least.