Simon,
check this out:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4950&item=5725475644&rd=1It's more than you need, but it's not huge and you get a LOC (line out converter) for cheap. Now you have an amp to last a long time and grow into.
I bought one just because the price was so low...
MArk