Well, GVT is a (relatively) high rep workout, at least considering that you are posting under strength sports. The whole idea is that if you truly need "advanced" GVT, then you have reached the point where 4-6 reps per set is pretty high, considering that its for 10 sets and with 90 second rest periods (which few people stick to anyway).
Anyway, if you really followed the "advanced" GVT program, I would say you should be in a state of at least some overreaching right now. I would recommend to do 2 or at most 3 sets instead of 10 sets of the same exercises you've been doing in advanced GVT. Use about 5-10 percent more weight than you finished with for your last week of advanced GVT. USe maximal rest between sets, and push each set close to your limit.
Lets just say you finished in the last three weeks with 10 x 6, 10 x 5 and 10 x 4.
For example, if you did in your last week:
10 x 4 Bench press at 225
10 x 4 Row at 185
2-3 sets of bench at 245
2-3 sets of Row at 205
all the rest you want, push near failure.
Try to get the job done in 2 sets, but you may reserve a third.
I would do this for 3-4 weeks. The sudden decrease in volume will help you recover.