Sorry, can't be much of a help being that I didn't book through an outfitter or travel agent.
Flew into Buenos Aires, stayed 2 nights there. BA was ok but next time I go I'll bypass that part of the trip and head straight to Patagonia. Flew from BA to Bariloche, which is in the lakes region of norhtern Patagonia
Have an Argentinian friend who lives in NY. She took care of all the reservations and itinerary Stayed with her and her family in Bariloche, AWESOME place, for 5 days. I went fishing with a friend of hers. He wouldn't take a dime even for gas as hard as I tried, great guy and we keep in touch via email.
Rented a car in Bariloche and drove ALL the way to El Calafate and El Chalten down in Glacier National Park. I wouldn't do that again either, way too long of a drive but did get to see a lot of the country. Spent 5 days in that area then flew back to BA for 1 night then flew back to NY.
Next time I go I'd either rent or buy a 4x4 truck that you could camp out of and skip the reservations and hotels. I hate trying to stick to an itinerary.
I'm sure it's pretty pricey if you book a trip through an outfitter but if your time is limited you probably don't have much of a choice.
The dollar goes a long way down there right now, it's 3+ Peso's to the dollar! Airfare is kind of steep but once you get there it's really cheap. Make sure you have extra room in your luggage for all the stuff you'll be buying. I picked up a real nice leather jacket for $134!
I suggest picking up some travel guide books and doing your research. A wealth of info in those books. If you have the time and doing your own thing down there and are going to be in the Bariloche area I could set up with my friend down there to go fishing. He has a RIB boat with a 25 Honda on it. He guides in the summer (our winter) and is a ski instuctor in the winter, great guy and catches fish too! I'm sure he'd be MUCH cheaper than booking through an outfitter.
If you're looking to go for like a week to just fish, check out some of the fishing forums and ask for advice. Here's one forum that I use, they have a travel section too. You should get some advice there.
http://reel-time.com/forum/index.php?s=b7f26436861322946c0c38fc68b5b6c4&
On my way home at the Buenos Aires airport, I met a guy that drove a Harley all the way from BOSTON with a friend on the back, took them 57 days! NO THANKS