I would say you're the equivalent of a 6-7 years of piano experience. If you follow the Vincent D'Indy program (I suppose not, since its from Montreal, but heck), playing the Appasonata is the equivalent of Grade 10 of their program. Grade 9 is averaging people who have played for 7 years and are around 15-16 years of age. Grade 10 is around more, but since you haven't played that much I'm guessing 6-7 years.
If its considered as advanced? Its definitly not too bad. 30 minutes lessons are obviously not enough, 1 hour is good enough. I would suggest a 30 minute program, or the equivalent of a final of first cycle of Conservatory.
If you have to prepare a prelude and fugue in two weeks, you must choose the easiest one. Not only is the fugue time consuming to finger and learn, it is also very hard to memorize them. I learnt the no.19 in A major quite fast, the fugue isnt particularly hard. The no.16 in G minor isnt bad either. Either way, you must look for the difficulty in the Fugue as it is most likely a lot harder than the prelude. You can even go with the popular no.2 in Book 1 I think
One of the hardest Prelude and Fugue of Bach is surely the A minor from book 1. I'm inclined to say this because its a 6 page 4-voice fugue.
Also, for the grades, I'm not familiar with the Grade 1-10 system, but my conservatory uses the following :
101 -> 105
201 -> 204
301 -> ...
I'm currently in 301, with 14 years of piano, I gave you as advice something in the end of cycle one, which means around 6 years behind me, which would spot you to 8 years of exp. For so around 104, your program should be around 30 minutes, maybe to 25.