Just back from w2r3, and I did it! Though my path was not straightforward owing to getting the gym opening times wrong...9:30 not 8:30, oops.
I have started building in some resistance training while I'm there too - why not, hey? Love the way C25K makes me feel like that! Got talking to the guy who works there last time and he showed me an endurance exercise that he says will help when running the 5K ...he seemed to think I was training for a race, it make me feel like I have to enter one now.
Anyhow, the endurance exercise is walking on the treadmill at 5k/ph at a 15 incline for as long as you can stand it. Then stop. Mine was 2 mins to start. He's super fit and is up to 5 mins, but as you see it's only a few extra minutes to add on and it will, he tells me, help the oxygen transportation to the muscles while running the distances that I one day hope to run, in that race that he seems to think I'm doing.
Will give it a try next time, seeing as I had to cut today short after the run.