desperate help needed asap please!!!!
 

so i bought a new motor for my scoot. everything was great runs great and everything. except one small problem. i went to put my tire back on and since mine is disc brake the back side of the tire is too small. i need help asap to fix this. i don't make much money and everything i make goes to support my dyeing girlfriend. this is how i get back and forth to work. my original rim is a j12xmt3.5 any immediate help to correct this i will gladly accept. thanks and God Bless