if it is using AA size batteries and is 1:8 scale then it is most likely meant to be played with as a toy. 800 is rather small by todays standards even for a battery pack made from AA size batts. you can get AA's up to 2500 mah in a nimh type chemistry at walmart and solder your own packs together. Check walmart and toysrus if you want to buy some pre made packs. they will be in the toy section at WM.
mah = milli amp hours it is a measure of the total energy a battery can store.
You can and should have fun with this car as you learn to drive. However, if you decide you want to step up to racing at any level, you will need to start over with a car that is designed for racing. Typically, they will use battery packs made from sub C size cells and will generate WAY more speed than what you have now. Additionally, you will be able to repair damaged parts or improve performance with aftermarket parts. The car you have now most likely is not repairable in the event that you crash it and break something.
Basically there are two levels of rc vehicles : the walmart/toysrus/department store types that are meant as toys and are basically disposable and the hobby type that while they may look like toys on the outside are really miniature versions of real race cars/trucks with all the same adjustability and options as their full size counterparts.
As for charging time on your vehicle, just divide the mah capacity of your pack by the output current of your charger and you will get your charging time.
Hope this helps