If it's a 110v DC motor, then you can get a
Kelly Controller, they are a cheap, Chinese made controller that tend to be under built and they self destruct of you push them at all to their limits, but they do make a 120v (18v to 136v) 100 amp (40 amps continues) speed controllers that they sell for around $300, so while I wouldn't normally suggest that a Kelly controller be used, their 100 amp controller would handle 16 peek HP for one minute, and 6.4HP continues, so it would be way more then you would need on a bicycle.
At that point you would just need a high voltage battery pack, a high voltage pack is going to give you slightly better range because of less line loss at the higher voltage.
Depending on your speed, it seems like bicycles tend to use 15 to 30 watt hours per mile, the faster you go the more energy you use, so lets say you get 10 12v 10amp hour lead acid gel batteries, that's 1,200 watt hours, lead acid gel batteries can handle slightly deeper discharges then flooded, so figure to 80% depleted you have around 30 mile range at 30 watt hours per mile, if you end up only using 20 watt hours per mile then you have a 50 mile range.
You could of course do some crude testing with your motor and a 12v or 24v battery pack and a simple switch to see how much push it gives you at a lower voltage to see if you could get away with running it at 72v or even 60v if you only want to go with 5 12v batteries, it would give you less speed, range and over all power, but it might be enough to fit your needs, or you might find it to be completely gutless, but it would let you find out without a huge investment in batteries and a speed controller.