WG, there are several things you can do to squeeze a little more from your budget, go with the girl ST on one night LT on another, saves you 1000 bht from your budget, take a free lancer or arrange to meet the girl after work, saves 500 bht bar fine. Find a girl you like and want to stay with for a few days, agree a reduced figure for 4 or 5 days together.
Your budget shows you have thought about it, know most of the costs and I'm sure will have a great time.
Oh another tip, look out for the big spenders and follow them from bar to bar, save on buying your own drinks, just lap up all the free ones from their bell ringing antics!!! ah just thought of another, look for bars with balloons outside, saves on food costs!! beggar at this rate you can afford to come here for free!!