I had a beer stuck at 1.020. After swirling, adding more yeast, moving it to somewhere hotter, etc it was still stuck (and too sweet for me) so on Sunday added Amylase Enzyme which is supposed to help.
I've written more info on AE here:
There is hope! « Homebrew Japan
You might want to read these also:
Before adding the AE:
Beer two is not going well « Homebrew Japan
Progress so far:
Progress update « Homebrew Japan
Since I am trying this for the first time, I can't recommend it or not recommend it, but I thought you should know about it.
Also, a number of IPAs tend to finish around 1.017 so you may just be "finished". I would be tempted to just take the beer as finished and start the dry hopping, maybe waiting a few days time if you want to be cautious.
In my case I used a kit with 1kg of spraymalt and was expecting 1.012. I didn't want to stop at 1.020.