Sandra,

As most have stated - sing away. Tune down 1/2 to a full step, it will make a world of difference particularly on those higher 'afternoon' phrase enders. Right now, you are straining to hit the last note on 'noon' - Ask your coach how to 'open up' on those notes - right now, I picture your chin extending and your head tipping back on that note. Try to practice keeping the chin in lower.

For the purpose of the couple of songs either live or on a CD, it will not bring down the quality - it will be something that will entertain and break up the monotony of a solid show of wordless gypsy jazz. I once got to hear John Jorgensn live, about 15 meters from the stage, and even though he is a master, it got to be quite boring after 4 or 5 songs. The singing and lyrics put an entirely different feeling into gypsy jazz. Make sure the lyrics tell a story. The history of popular music is ripe with examples of singers much much worse than your voice, but they were great storytellers. One could argue that nearly the whole of country music singers, with some rare exceptions, actually have terrible technique, but again they are great storytellers. Work on your facial expressions, gestures, interaction with the nearby audience members, etc. just as much as you work on what little is left for vocal technique. Your audience will love it. Most of all, have fun - that will shine through above all.