Sorry to hear that they found dysplasia (precancerous tissue). Some mild cases of limited dysplasia can be monitored more regularly and you can live with it for a while. You can ask if that's possible for you (it may or may not be). Often, dysplasia means removal of the large intestine. It depends on how much and how far along it is.
The j-pouch is the standard go to surgery for uc patients. They construct a pouch out of the end of the small intestine and attach it to the rectal cuff on your anus in 2 or 3 surgeries depending on patient health and whether your currently on corticosteroids (like prednisone, better if not on them). You maintain standard bowel control and poop. The other option is an end ileo, which gives you a stoma and colostomy bag.
Do your homework, get a surgery consultation to ask questions and answers about
your concerns. Visit the ostomies forum on healing well and ask about
the surgery, recover from those who've undergone it. Visit jpouch.org. When I was flaring badly, I found this blog to be helpful
ronnielee-fightingforit.blogspot.com/2012/08/coming-to-terms.html, a former healing well poster who blogged through her jpouch surgery and recovery.
Notsosicklygirl (a uc moderator on healingwell) is undergoing step 2 of 3 of the surgery soon. She's a great resource. There are a few others here as well recently done with, or undergoing it.
Good luck,