First off, get away from Benezia. I suggest running to the right, as that instantly puts a wall between you and her, and since she doesn't move, you'll just have to worry about the Asari Commandos now. Please note that you're going to need to be slamming down on the stick before the cutscene ends in order to get out of the way fast enough.
After that, put Wrex at one end of the corridor, Garrus at the other, and support them as needed. Wrex should be able to handle himself, so watch Garrus. Use your power liberally, along with that of your squad mates. Once the first wave falls, another wave will come in. Wait for your powers to recharge before engaging them. Rinse and repeat. Once all the waves are down, go after Benezia.
On a side note, you should bring Liara instead. Not only can see resist biotics better--and toss the Asari Commandos around easily enough--but you also get some bonus dialogue.