Hey guys, desperately need some assistance with the following, would be much appreciated.

Interest Only Loan, 10 year term, 7.5%pa comp monthly i, $50,000 principle
Monthly repayments are $322.92

I need to calculate what the monthly repayment would be if the interest rate rose by 3% to 10.75%pa at the 5 year mark.

Am I right to assume discounting?
Any help would be great, cheers!