@sohailazeem Well, if you can manage to find a used Honda CG-125 is good condition within your budget, then I'd definitely recommend you The 125...
Besides, there isn't much power difference between a 70 and a 100... It's just a mere 30cc difference, a 100cc pulls a little stronger and that's about it...
I rode my cousin's Road Prince 100 and all it had was a bit more 'poke' at low revs compared to a 70... Nothing miraculous and not even close to 'sporty', I'd like to add... It's gearing felt about the same as 70cc, so it won't have that much more top speed than a 70 (Provided TOP SPEED is your thing!)
A 125cc, on the other hand, is a proper upgrade from a 70cc, specially the ones with a 5th Gear and can be pretty fun if ridden hard...
Rest is up to you, brother...