Sorry dude guessing a time frame on abs is tough...I say train them ~3 times/week and concentrate on weighted movements for med reps:

Decline crunches(weighted with a plate if possble even if you have to start with a 5lb plate)...Concentrate on exploding up,and slowing down the negative(down)
cable crunches /rope-Yes a rope like you would use for triceps...slow up,and down witha nice squeeze at the bottom
Hanging leg raises--Hold for about a 3-5 count then down


I would do 3-4 sets of each with reps in the 10-12 range...Oh yeah it will burn...