You can get the whole engine, tranny, axles, and ecu for about $400-$500 from boards. Check on honda-tech.com, d-series.org. Someone is bound to be selling a D16Z6 swap or head (which is what you have).

Here is a link for a head for $300, but you can find better deals than that buying from someone.

http://www.sohfast.com/store/used/civic.asp

Here is a whole engine for $350, I'm sure he's nego.

http://www.honda-tech.com/zerothread?id=1124153