How's my 85 f1.8?
. . . and please remember that when you are using the reciprocal rule to figure your minimum shutter speed, you need to multiply the focal length by 1.6, since you are shooting a crop camera. So, for purposes of the rule, your 85 is really a 135.
Also, regarding the question of shutter speed vs ISO, I feel your pain. I really try to keep ISO down to 800 or better where possible. That said, when you have to choose one or the other, you are almost always better off going to a higher ISO, if that's what you need to do to maintain an adequate shutter speed. Fighting noise is no fun, but there are some great tools that can be remarkably effective when used properly. Blurry images, on the other hand, cannot be saved. Whether the problem is camera shake, or subject motion, the only tool that works on blurry photos is the delete button.
And last, if you don't have a tripod, get one. In the battle between shutter speed and ISO, your tripod is your best weapon. It won't help with subject motion, but it is the very best tool for beating the camera shake issue. A really good photographer once opined that, "if you're not using a tripod, you're not serious."