Suggestions please!

Hi everyone,

So, my sister is getting married August 3rd. Only 20 weeks away! Yep, already counted. Here's the thing: I lost about 26 pounds last year, but it took me seven months to do it. I felt great, but ended up having two kidney stones within a month of each other and I got out of the habit of eating well/going to the gym.

Here's where I need your help: I'm going to be in these pictures for the rest of my life, and I'm going to be the maid of honor. I would love to look as good as possible by the time August rolls around, but I also want to do this heathily (is that a word?). What suggestions do you have for the best way to make a noticeable difference in 20 weeks? What has/hasn't worked for you? Thanks in advance for your help!