It's a pretty easy fight
After getting over the shock of the three tremendously large breasts, grab the explosives in front of you then head to your right and collect the Rocket Launcher. Lay a few trip mines near the middle and then throw a pipe bomb off the bouncing pad. making sure to detonate as it gets close. Once her guard is down fire as many rockets as you can before she reacts. Repeat this a few times and she will launch a few of the flying heads, stay in cover from her attacks while you take them out and this fight is over before you know it.
http://www.gamersheroes.com/duke-nukem-forever-boss-guide/ Has a brief guide for each boss if you're struggling :D
