Thanks for all the replies. We were originally scheduled for lessons the weekend that Ike it - so haven't had the chance for that yet. I've read a lot - the ASA book, several others and have watched most of those videos that were recommended - they are excellent. The reading taught me to turn into the wind, let the mainsail out or to hike out to counter the heel - I did the first two and was already sitting on the windward side when it happened (as was my partner). It was the sudden shift that scared us!
I think the suggestions of reefing the main and making the genoa smaller were what we should have done after the first time. After the 2nd time, going with just the mainsail was pretty stable.
There has been only one day with any wind the past 2 months on the lake (the day after Ike passed nearby) and so we were excited to actually sail instead of motor around the lake.
This forum is really a great resource, and thanks again.