I agree that going from no running at all to running a full 5k is a lofty, probably unrealistic, goal for just two weeks. Definitely check out the Couch to 5k training plan and see how you do in the first week. Be careful not to push too hard, because even though you're already healthy and fit, your muscles and joints aren't conditioned for the high impact of running. Running too far too soon could lead to injury. I think doing a mix of running and walking would definitely be your best bet.
Good luck and have fun with it!