It's unrealistic because youre talking about gaining 80lbs in a lift in a few months, which is possible if youre a beginner under optimal conditions. However, not in an exercise like curls. Maybe squats, or deads, but like I said, only in a beginner under perfect conditions....
The biceps are a VERY small muscle group, they don't have the capability to shoot up that fast. Not to mention, the rest of your body actually plays a bigger role in your curl poundages than curling itself.
Increasing your deads/squats/flats/rows/chins along with a drive up in bodyweight will all lead to a bigger curl, your body needs to get strong and grow all over before your arms will grow at even a decent rate.
So, if you want a realistic answer to your question on how to get to 200lb curlzzzzzz, then here it is:
1) increase your deadlift, and squat each by about 250-300lbs.
2) Do chinups until you can get sets of 15, then add weight each week, until you're doing a few plates for at least 10 reps.
3) Increase your bodyweight by about 100lbs.
Around that time you should be able to curl 200lbs.