Hi there!
I wouldn't pitch new yeast just yet. What's the yeast you pitched originally and what's the temp you have the beer at right now? I would make sure it's on the warmer end of its range and maybe try to agitate it some. Two weeks into fermentation and being stuck at 1.020 is not a great sign but it might restart for you.
With a stout a little extra time shouldn't hurt too much. I'd give it a little time, maybe a few more days or so, and if it's stuck at the same gravity then maybe try to get a small starter going and pitch active yeast if that's possible for you. If not then just pitch what you have however you can.
In my earliest batches I had a couple that quit short and just never restarted at all. Don't be disheartened. It could be some issue you had with your mash, an underpitch of the yeast the first time around, a temperature drop as the fermentation was slowing down, or something else. Just look back through the process and think about it for next time.
I'll let someone else weigh in on the bottling, for sure, but I probably wouldn't bottle it in the current condition. That sounds like a decent amount of fermentation left to do. Probably wouldn't be the best beer in the bottle
and you're risking it taking back off after bottling and giving you bottle bombs. Not fun.
Good luck and let us know updates