Thank you for reaching out to us.
We are sorry to hear of your injury and ensuing difficulty walking and moving.
There are two main options in this situation. The first is to find a mikveh with a lift that would lower you into the water, and hoist you back out again. You can reach out to your local mikveh for information or feel free to get back to us here with your location so that we can try to research the matter for you.
The second option is to arrange in advance to go into the mikveh with human assistance. In this case, you could wear a long, loose t-shirt into the mikveh. A friend or attendant (or two) would hold you, either from the edge of the water or entering the water with you. If you cannot stand on your own, then they can hold you during immersion as well, as long as their hands are wet with mikveh waters before taking hold of you and they loosen their grip a little (without letting go) under the water.
We hope that this helps and wish you a refuah sheleimah. Please let us know if we can be of further assistance.