I want to make some improvements on it if i don't find someone to sell it because my girl dose not like it as a bicycle
This might not matter at this point, but in my experience it is better to have someone find the bicycle they like *as a bike*, and then convert it to electric, keeping in mind how they like to ride it and what performance degradation it will have on riding it as just a bicycle (extra weight, changes in steering/handling due to weight placement, etc--all of which can be tested beforehand by placing just weights or bricks or whatever in the same places the ebike stuff will be, riding it, and seeing which placements make it a better bike).
The kit came with a no name controller that feeds the motor 7A .My battery is a LIPO4 36 volt 10 ah pack.If i upgrade the controller will the motor run better ?
Depends on what you mean by "better". If you want to go faster, you'd need higher voltage. If you want better acceleration, especialy from a stop, a higher-current controller might help, but only if the battery is capable of putting out that current without major voltage sag.
What you want first is a wattmeter, like the http://ebikes.ca
Cycle Analyst or Watts Up or a number of other wattmeters, so you can monitor the voltage and current out of the battery into the controller while riding the bike in various situations. THen knowing what is actually happening with the existing equipment, you can decide which parts need replacing to improve it to the point it does what you want it to.
Also i was wondering if someone can use capacitors as a power supply .If anyone tried this i will really appreciate the input.
If you mean in place of a battery, then with typical caps you would need a huge bank of them, perhaps the size of a car, to run your bike as well as the battery you have now.
With really good and expensive caps you might be able to use something a lot smaller, but it would still be bigger than you and the bike, because you must store enough energy so the voltage remains high enough to be useful.
Basically you have to have probably ten times or more the capacity in capacitors than you would in a battery, because the battery's useful storage is all at higher voltages, but capacitors store it across the entire voltage range from zero to max voltage. Controllers and such can only use that narrow higher voltage range, so you're stuck with wasting almost all of the energy storage space in the capacitors just to have enough energy to run your system.
It's possible to create a controller that would use a much wider voltage range, and use more of the energy, but none of the typical ebike controllers are capable of it.