Replace with the GM PP bar and you'll be happier than you were before. For the cost, it's not worth trying to repair.
i would replace the end links also which hold the sway bar
when mine broke i got the GMPP front and rear with poly links and couldn't be happier. its definitely a noticeable difference and was pretty cheap i think i paid $120 for both bars and both sets of links from my dealer.
if he sway bar isnt broke then by all means just replace the end link.