I want to really tone and tighten my upper arms for a wedding in June (sleeveless dress).

To be more specific, I have lost over 60 pounds, in a little over 2 years. I see that my arms are smaller than they were, but I still have what looks like extra skin, or possibly just lack of tone in the back of the arm. I actually like to lift weights, but I don't have equipment to use right now, and I can't afford the gym. I have been trying to use 10 pound weights meant for the leg, and just wearing them on my wrists as a make-sift weight lifting session.

With this in mind, what should I do to get them in great shape, and is it a realistic time frame?
Thanks!