Yes, as said above, you would need a low voltage receiver and a brushed esc. If you don't have those, than you really should look for a new plane that's a bit bigger.

As far as the battery goes, lipo isn't the only option, you can also use lifepo4. BUT, they are heavier, and herd to find in 1s, so you would have to un solder the cells. So, lipo is likely gong to be the only option for a plane of that size.