Christina Milian

IMDb lists it as:

“Famous”
Performed by Misty
Written by M. Gonzalez, A.Lane and M. Haene
Courtesy of ETNC

If it’s the same Misty Gonzales who has done other songs for TV and film:

She is the lead singer of a band called Freedom Child:

I wasn’t able to find anything else that mentioned that particular song, but there’s enough contact information within those links to help you find out whether or not it’s available to buy.