You've certainly got time to go somewhere in Patagonia, but as the others have said, it's quite a large area, and you need to narrow it down a little.

Bariloche/Lake district is lovely in itself but it's not really Patagonia - it's got trees for a start

Patagonia itself is quite windy and desolate for the most part - there's great hiking around Calafate/Chalten, and obviously the Perito Moreno glacier, but otherwise it's generally great landscapes rather than real 'wow' stuff. There's a load of lakes, not just in the lake district - we crossed Lago General Carrera which is an incredible blue colour from the Andean glacial run-off which fills it. The size and the distance between places means that if you want to go to Patagonia proper then you need to fly down to Calafate and base yourself there. However, unless you're keen hikers or riders, there's probably only a couple or three days worth of things to see/do - the glacier, walk in the woods, evening eating great pizza and drinking cheap beer in El Rancho .

Personally I would think that Bariloche would be a better base for a few days if you're not hikers - there's loads of organised excursions (white water rafting, cycling, riding again, etc) but it's also quite a big town set on a very pretty lake and surrounded by lots more very pretty lakes.

Have a great time whatever you do - we spent six weeks in Argentina a couple of years ago and loved every steak-filled minute