After 3 weeks, the beer is done and you can bottle. The bubbles that you are seeing is probably C02 coming out of solution. Take a gravity reading and compare it to your OG. If it's an average gravity (under 1.055) beer, it's done if it's between 1.010 and 1.014.
The Biz Brewing Co.
Canadian ales for the people
Primary 1: Rigo's IPA
Primary 2: Sweet Mama Barley Wine
Primary 3: empty
On tap 1: Cascadian Canadian Lager
On tap 2: SNPA American
On tap 3: SNPA English
On deck: Columbus IIPA
On deck: Marco's Vanilla Porter
On deck: Wild West Am. Wheat