That FG is not at all out of the question for an extract brew. (We'd still love to hear your OG if you measured it) I just had an IPA finish up at 1.020, which was about 5-8 points higher than I had hoped, and it's far and away my tastiest beer yet. I wish the ABV was a point higher (yeah, I like to get buzzed, sue me
) but I'm much happier having this super-tasty beer that I am very proud of, than if I had risked screwing it up by adding more fermentables late in the game. And uh, it still "works", trust me!
If I were in your shoes, I'd wait another week or two to let it condition in the primary for a bit, then bottle it and enjoy. If you want a stronger beer, brew one next time rather than try screwing around with this one.