take it easy, dont run it at WOT and get some higher (91 or above) octane gas in it ASAP. If the gas is the issue and it is causing a misfire, it will go away in time after you get the new gas. It will not go away instantly though, but you should notice your car running better. It does seem to run OK when you are not getting on it, right? You could have just gotten bad gas too(water in it?) you could try and put some Heet in it at the next gas station-make sure you get the right kind. This will get rid of the water in the tank, if you have any. just get new better gas in it asap.
