Just wondering what your $20 a month payment to Banfield covers? Is it just visits or is it some type of insurance that covers accidents? Did the vet tell you to stop the meds there were prescribed or did you just do this on your own? This might be the reason that she is not showing improvement if it was an anti inflammatory that was to be given over a period of time but was stopped too soon I would think that you would not see results as expected.
What do you mean when you say she has a lame leg? Do you mean that she is not putting any weight on it at all, hold it up, or limping? Did they mention anything about her possibly having LP? All 3 of mine have some degree of LP so I need to watch that they do not jump but they have all limped in the past from doing something they should not have

If I were you I would just pay the money for the Xray to make sure there is not a break. Poor thing always seems to have something going on