It depends a little bit on how badly it's warped but, most likely, that much out-of-trueness can be adjusted away. A bike shop will most likely charge you between $10.00 and $25.00 to do the job. Depending on what they actually do, $25.00 may be a bargain and $10.00 might be a rip-off.
The right way to do it is to check each spoke with a tensiometer to make sure the spoke tension is equal on every one, then true the wheel by tightening and loosening opposing pairs of spokes until the wheel is both round and straight from side to side. That would be the $25.00 version.
The quick, dirty way is to find where the rim rubs the brake pad, and tighten the spokes on the opposite side until the wheel looks straight. If you want to try doing this yourself, take your wheel into an LBS to make sure that you get the right sized spoke wrench. Spoke wrench sizes aren't very different, but too small won't fit at all and too big will round off the wheel's nipples.