It would be very difficult doing both in the same year, I'd say. I'm only doing AS - on a maximum of one lesson a week, although it was occasionally 1.5 last year, so I did two modules in Yr. 12 and will be finishing off the speaking this year - and that's not too bad; standards do seem to be lower than, say, German, presumably in attempt to encourage people to take it, and to account for the fact that Russian at an advanced level is just plain hard. But A2 is another step up again, and you'd definitely need to have a very good teacher to be able to get through it successfully. As everyone else has said, it just depends on how much time you're willing to commit; e.g. my school won't give me frees, and I know I couldn't have coped with another A2.