I would say book and keep track of your flights and see if a sale pops up before then.
I'm doing off days for my trip out of Baltimore (non-stop Airtran) and looked for the same thing. Hoping the price would drop or a good sale would pop up and it didn't. We jumped on prices when it was about $400RT pp and since then the price has steadily gone up, even on the good midweek days.
In the past I've booked and if a good sale popped up; I called customer service and they charged the change fee but I still got a credit for the difference that was still there. It doesn't look like too many airlines are running those great sales anymore sadly. Just my opinion.
Hope it works out.
