You can try TabTrader for Bittrex. I used them in the past and it's good. I don't know about Yobit, not so many apps support them. Why don't you move those dust coins to your Bittrex account?
Yeah that is the possible way to do it.
Or you will be scouring something which takes time. A lot of time.
I have done that before and I just failed.
Besides, you are just trading for fun or it could really be a good training for you.
Good luck.