You can try using less assist by letting the car rev higher through all the gears. This will drop your mileage, but you can pretty much drive so that you use no IMA, just bring it to 5000 rpm in first, not necessarily hard acceleration either. Just dont really get on it or you will get IMA, then accelerate predominantly in 2nd, as long as it's above 3000 rpm and not wide open throttle you can drive with no IMA. I do this durring the summers to try to keep the heat off of the battery pack until the car cools down. You can also just put the car in neutral in your dirveway and rev it to 3000 rpm and it will force charge to one bar from full. Once it's full you can try that and see where it stays.
or
You can reboot the car and force a recalibration which will generally end in a full charge. Just disconnect the 12 volt battery for 15 seconds and when you start the car again the charge will be 0 and you will see a force charge, you can either drive it around, or let it charge then rev to 3000 to force charge the rest.
Neither of these are probably necessary as it sounds like driving conditions to me. Just try your best to coast as much as possible and try getting the most you can out of regenerative braking. Try timing it so you don't have to use the mechanicaly brakes until regen cuts out at 19mph. Good luck.