You need to give it some real rest... take a week off, with plenty of ice, compression, and elevation. If it is a mild grade sprain or strain, you should see the swelling start to go down after the first 48 hours, and you can then stop with the cold therapy and start with heat therapy. If the swelling does not go down, get to a doc.
In all reality, if you've had noticeable swelling for two weeks already, you might just want to skip all of this and get straight to the doc. If you already have a grade 2 Achilles strain (the tendon is torn but has not yet parted) you need to get medical attention. That joint sees a lot of action throughout the normal course of daily life, and you don't want an already destabilized Achilles (if that's what the problem really is) to tear completely. But first things first, stop running. I got to see a grade 3 Achilles tear once and it's one of the few times a sports injury has made me throw up.