Bicep Increase - Noob speaking

i'm new to this forum and i was just wondering if anyone had any tips to increas the bicep size? i work my biceps 1x a week along with my back and i got heavy on them. i do the following excersizes with the amount of weight:

Dumbbell Concentration Curl - 3sets :: 8 - 12reps :: 25lbs - 30lbs - 35lbs
Barbell Preacher Curl - 3 sets :: 8 - 12reps :: 55lbs - 65lbs - 70lbs
Standing Barbell Curl - 4 sets :: 6 - 12reps :: 50lbs - 60lbs - 70lbs - 75lbs

i also go heavy on my back because i have read that if you go heavy on the back, your biceps get bigger and if you go heavy on the chest, your triceps get bigger.

anyways, here are my current stats incase anyone needs them:

18years old
6'
216lbs
13% body fat
18.5" biceps
49" chest
bench press around 335 - 350lbs

i'm currently on a No Carb diet to shed some body fat for the summer. i keep my Protein level to about 300grams per day. around 40 - 60g each meal. i will increas my Protein intake to about 360 - 400g per day when i can afford supplements...

o'yea... 2 days a week, i'll eat about 50g of Carbs. mostly on the days that i work my biceps & my triceps. i work them seperate. i'll eat about 15g of Carbs pre-work out and about 35 - 40g of Carbs post-work out to help preserve muscle mass.

any tips on how to increas the size of my biceps? i'd like to reach 21" biceps before next summer.

My favorite is dumbell preacher curls. Hammer curls will add girth to your arm. Reverse curls on the preacher bench are great for brachioradialis size .Also triceps are 2/3 of yor arm size. You must work them from differnt angles for maximum gains. I can't do barbell curls because they hurt my shoulder but they are also good with correct form.