Since you were planning on removing the carpeting anyway I would recommend going ahead that. The only thing is that you should also replace the underaly incase the urine had soaked through. Once you are down the the bare floor, treat (i.e. clean or sand down) the area where the urine had been. When the area is dry then paint it with a sealent (just like you would use on an outside deck). Once that is dried go ahead and put down the underlay and new carpet. You shouldn't have any trouble in that spot again.

If you get the curtains dry cleaned that should remove the smell of the urine. (My cat pee'd on my duvet and once it was drycleaned, it never happened again).

Good luck.

Cheryl