Stef,
Good Advice. Need to make sure the sights are the problem.
Derek,
How tight are your groups? If you're putting a 1" group 3" left at 15 yards, it's likely the sights, because that's a very tight group for someone who pushes the trigger. On the other hand if you're putting a 6" group centered 3" left at 5 yards, the groups aren't consistant enough to draw much of a conclusion.
There are also 2 other possibilites
1) Pick up or borrow a pistol shooting vise/rig so you can remove yourself from the equation and fire a 5 shot group.
2) Pick up a chamber bore-sighting laser and compare the center line of the barrel to the center line of the sights. At least my experience with an in-chamber bore-sighting laser has been that they are almost dead-nuts in azmyth, but don't have any bullet drop adjustment for vertical, so you should see right or left bias in the sights, even if the laser is off up or down.
Last thing:
My dad was a police officer for 26 years. He was a very consistant shot with his pistol, shooting about 3" groups at 20 yards, free standing slow fire, but he pushed every shot almost 6" left at 20 yards. He intentionally drifted his sights to compensate and did beautifully with it. When I shoot his gun I shoot groups 6" right at 20 yards (I've since learned to compensate with point of aim) but that was his solution for more than 20 years.
