You can buy full electric window kits for cheap these days, people usually buy them to retrofit into cars that came with winding windows - no need to fit a nissan one or an exact replacement
Sticking halfway up means that your motor is probably worn as well as the plastic geared parts (not sure what it's called) - even if it's sticking a strong motor should have the torque to get it up if all those parts were in good condition, it'd just squeak. Once the squeak starts everything gets worn quickly since it's only cheap plastics working against the friction resistance of the rubber seals and weight of the glass