My sister hooked up jumper cables to my 2002 kia sportage to jump her car. she hooked them up wrong and now my car wont start

At least your sister was not injured by an exploding battery - that is a probable outcome of reverse charging.

Does the engine turn over at normal speed? If not, try recharging your battery.

In any case, it would be a good idea to check your charging system to make sure the voltage regulator is still good (this is usually part of the alternator).

If the engine turns over normally, but won't fire, try doing a computer reset - the computer memory may have been corrupted by the reverse voltage. This is done by disconnecting the ground cable of the battery for a minute, then reconnecting it, or if it is available, disconnecting the ECM power lead rather than the battery ground. (Caution: if your car radio has an anti-theft security system built in, check the manual for the proper procedure first. Failure to follow this procedure will disable the radio.) In the worst case, the engine control module or some other part of the control system was damaged.