Pay a visit to Malik owns located in Khudadad colony, Its near Quaid-e-Azams mazaar, once there ask for Ghazanfar, give him my reference (Usman from Defence Ph-5) mention your budget to him, hopefully he will either have a bike within your range at his workshop or he will arrange you one. However, his asking prices will be a little high but doesn't mean you have to consider them final, he will negotiate as much as you negotiate so until you think the price is good do not hesitate to bargain. His number I know must have been alot helpful for you but since I am not in the country I cant locate it for you. Rest assured there is a high possibility you will find what you are looking for once you do pay a visit. Take a good look at the bike you're willing to purchase if you find one within your budget, test it out accordingly before giving out a token. PM me if you need any more info regarding that or infact anything, I'd be glad to help you out the best I can. Good Luck and Ride Safe!
p.s. go for a higher model bike i.e 1992 above, that might come a little expensive (depending on condition) but wait it out till you can afford it since the wait will definitely be worth it in the end.