I like to keep track of flights using bing.com because it keeps track of the price trend to let you know if you should wait or buy now.
I wouldn't lose hope yet that you won't be able to get low airfare. Currently the lowest price I am seeing is $239/person but at least the prices aren't on an upward trend. Just keep watching. You never know.
ETA: Also with the way flight baggage costs are these days keep that in mind. Just because a flight is more expensive on one airline vs another, it may be cheaper in the long run if you plan on checking baggage (ex. southwest has free baggage whereas US Airways charges $25 for the first bag).
ETAx2: Actually check
southwest.com! As long as you aren't worried about getting a refund there are quite a few choices for less than $150/person! Good luck finding what you need.