Diet and exercise is the key. LISS and HIIT both have studies showing they are the best at burning fat vs muscle, so whichever you're more likely to continue. Toned arms would be the result of tricep exercises, of which there are literally hundreds to choose from.
As far as supplements, there are a lot of options. Have you ever taken anything with Yohimbine? Very effective, but some don't tolerate it well. Radiate from RXS Supplements has several logs on here, and I know of a few women who have taken it with good results. You can also go with the standard ECA stack, but I would cut the dosage down quite a bit at first so you can see how you handle it. I'm sure you'll get plenty of suggestions on fat burners soon.