If you only have a week near Anchorage, start surfing now and make a plan. The time will go faster than your $$ - and they'll go plenty fast.
Find the Anchorage Convention and Visitor's Bureau web site,
http://www.anchorage.net/the Alaska Dept Of Fish and Game web site
http://www.state.ak.us/adfg/adfghome.htm has a ton of stuff including weekly fishing reports, general fishing planning info and so on.
Or look into fishing out of the Willow and Talkeetna area - there are jet boat services, air taxis, guides, lodges, day trips, or overnight opportunities.
I August there should be some silver salmon fishing going on in quite a few places.
There is lots to do but there are usually a lot of tourists so some things can be booked up fast. A day cruise out of Whittier or Seward is always nice - or charter fishing. You might even be able to fish at Ship Creek right in down town Anchorage - depends on what you like to do.
Good luck.