What should I do so i won't be embarrassed by my family when they meet my in-laws?

[flannagain]

My mother-in-law wants to meet my family to celebrate my engagement but i'm embarrassed by them.
My mum and dad always argue when they are put in the same room together and fight in front of anyone they don't care who hears. They both drink large amounts of alcohol and refuse to put down the bottle no matter how much I ask them not too. My dad also smells horrible and even after he has a bath, he still smells of booze and fags which is very unpleasant.
It doesn't help my partners family are so caring and don't drink. I don't know how to put them all into the same room without hiding under a table.
Can somebody help me please?