What, you haven't sighted it in yet? Jeez...
Go forth and buy a decent scope. Got $200? Go pick up a Bushnell 3200 3-9x40 and rings at your local sporting goods store.
Get a cleaning kit from the store while you're there, nothing fancy. You're going to need a steady setup to rest it on at the range table. Sandbags, jackets, whatever, you just need a rest of some type.
Have the store laser boresite it when you buy the scope (most provide it for free). If not, pull the bolt and look through the bore at a target and adjust the scope till it's on the same target. This boresights it.
Go sight it in, starting out at shorter ranges if necessary. The boresight is to get it on paper, the live fire will be the the final adjustments Fire some more to make sure you have a good zero. You'll want to zero it for mean point blank range, google it to find out, or wait for someone to come buy here and tell you what that is for .243.
You'll have to hope you can find .243 ammo on the shelf. Buy a few different brands, a couple boxes each and maybe you'll find something that shoots the best, but any standard softpoint suitable for hunting should give you good enough groups.
Clean it before hitting the range, don't bother with the barrel break in BS.
How to sight in:
http://www.vortexoptics.com/content/sighting_in_your_riflescope_part1
http://www.vortexoptics.com/content/sighting_in_your_riflescope_part2