<p>Is there any good software that will allow me to search through my SVN respository for code snippets?  I found 'FishEye' but the cost is 1,200 and well outside my budget.</p>

A lot of SVN repos are "simply" HTTP sites, so you might consider looking at some off the shelf "web crawling" search app that you can point at the SVN root and it will give you basic functionality. Updating it will probably be a bit of a trick, perhaps some SVN check in hackery can tickle the index to discard or reindex changes as you go.
Just thinking out loud.