Most people would have more shake issues with the telephoto (with or without image stabilization) than the fast 50mm lens. That leads me to believe that you're new at using the camera. Therefore, please forgive me if my assumption is incorrect in the following suggestions...I don't want to insult your intelligence...but for a noob, I think these comments are appropriate.
1) Since you seem to be a noob, pick up a book on your camera and learn the basics of good photography technique. If your light is too low, your shutter speed, aperture settings or ISO settings will be such that you simply cannot hand-hold the camera without blurring. In that case, you have two options; tripod or flash.
However, since low light photography is the ABSOULTE most challenging situation in SLR photography, you need to learn how shutter speed, aperture setting and ISO can be used to your advantage. By reading about basic DSLR photography 101 and understanding how these are three inter-related with each other, you'll learn the limitations of hand-holding with the camera that you own...such that you'll know that you've sqeezed as much out of hand-holding as possible and you need to then implement either a tripod or flash technique.
Also remember that in DSLR photography, there's nothing wrong with taking 5 or 6 or more shots in order to get one shot that's not blurred. The advantage of DSLR is that you can shoot as much as you like without any additional cost. In the old days, this was tough because you wasted alot of film and $$ for processing.
2) Since you seem to be a noob, learn to hold the camera for maximum stability. Many noobs grasp the camera like noobs...one on the left of the camera body and one on the right...from experience this isn't gonna provide the most stable shooting base and can lead to extra blurring. The better technique is to cradle the camera with one hand beneath the camera...palm up-turned supporting the camera. This allows your thumb and forefinger to be free to operate lens settings, focus rings, etc, if necessary. It also allows you to bring your elbows in and brace them against your body...which is good technique for minimizing camera shake (use your body as a tripod). Use your right hand both grasp the camera body and to reach up with your forefinger to operate the shutter release.
This technique is basic photo 101, so please forgive me if this suggestion insults your intelligence, but given how many noobs naturally clutch the camera with two hands the first time they pick it up (one on the left of the body and one on the right of the body), it's a worthwhile comment I think.