Unless you are already at or below the legal minimum, don't get new tyres just before you do a trackday. I did - the edges of the tyres look decayed already, I lost a lot of rubber off the outside edges and I had the get the wheels re-balanced due to excessive wear the following week. Get them after you've done it (unless you're going to do a lot of miles in the next couple of weeks). If you find your fronts have gone completely after a couple of hours on the day, just swap them with the rears.
One other point, if you use reno recommended tyres, I found the contis were superior to PE2s on track, they went off slower and there was less understeer.
I can't help you with where to get tyres in your area though, sorry!