Any behavior that you teach with a lure can be transferred to just a verbal command very easily. You do it in several steps:
1. Using the lure to get the behavior. This is the step I think you're on now. By the time you move on to step two, you'll want the behavior looking more or less like what you want the finished behavior to look like - i.e., this is a good time for you to teach her to limp towards you. Lure the same way you have been, but pull her towards you instead of to the side.
2. Fade the treat. You can start by luring with a treat and then giving her a treat from your other hand, this usually helps dogs figure out that the treat lure isn't really that important. Sometimes you can skip that and just take the treat out of your hand altogether. Hold your hand the exact same way you'd been holding it with the treat (act like there's a treat in your hand), and use the same hand motion you used with a treat in your hand. Sometimes it helps to gradually fade the lure - do one trial without a treat, then one with; then two without a treat, then one with; etc.
3. Add the verbal cue. Up until this point, she's too interested in the treat or your hand to really care what word you're saying, so it doesn't do a whole lot of good to start to add the verbal cue until you've at least faded the treat lure. I just say the verbal cue, pause about 1/2 to 1 second, and then give the hand signal as before. So the verbal cue is the predictor of the hand cue, which is the predictor of the behavior. After 5-10 trials like this, then try saying the verbal cue and waiting 2 seconds before doing the hand cue - giving your dog the chance to do it on her own. ANY attempt to do the behavior should get rewarded at this point - even if just with praise and encouragement. If she still isn't doing it without the hand cue after 5-10 more trials of waiting two seconds, then wait longer and longer, until eventually she should do it.
4. Start generalizing the behavior. This includes doing the behavior with you standing up. Make slow movements toward the standing position - first get her doing the behavior with you kneeling on the floor; then with you squatting; then gradually moving higher and higher (also a good leg workout). If at any point she has a problem figuring out what you want, you can add your hand cue for one or two tries to give her the idea again, but be careful not to use it too much. Once she's doing it with you standing, then you can generalize to other positions (for example, limping in a heel position), and in different places (your kitchen, outside, etc.).
Let me know if any of this does not make sense. Good luck!
