RUNNING THE MILE HELP!!!?

well, in my school, i am now known as the number one girl SPRINTER. this spring, we will have to run the mile and if i cant run it in about 7:30 or maybe 8, i loose my title. i ran the 60 in about 8seconds at a cl race, and no one expected it from me. i expected to get 3-4th place, but never 1st (2nd overall because of the boys) since i have always been fast, but not number one, so how do i run the mile? HELP!!! (i currrently run the mile in about 9:10 the second time i ran it...this went down from a 12 the first time i ran it) also, would riding my bike 5 miles a day help? because i do everyday