Aye, just undo the 4 screws at the corners of the red lense and it will either fall right off or require just a touch of leverage from a flat head screwdriver, key, quarter, etc. It's also labeled on the lense which way is up for when you put it back on.
Any auto parts store should be able to give you the right bulb. I say "should" because sometimes they goof. Put it in while there so you can go back inside if it's not the right one. Shouldn't be more than a couple bucks. Avoid handling the bulb itself with your fingers. Oils from your skin will shorten the new bulb's life. Often dramatically.