Your lucky you got that many miles before this happened. My 99 only got 74,000 before the gaskets gave way. According to my machanic, the 96-99 2.5 were notorious for this problem because the factory installed gaskets did not have an etched surface (grabs the head better and prevents slippage).
Anyway, he said about 3,500 to 4,000 (prices may vary, this is Alaska after all) for a shortblock or the 2,000 for a rebuild. I went with the rebuild but that also included many extras like a new timing belt, head shaving, rollers, etc. that he found to be worn out.
Hope this helps.