I am so sorry,it must be despreately worrying for you not to know where or how your cat is.
If you contact your local branch of Cats Protection(the UK's largest Cat Charity) they have a Lost & Found register,which might help,as anyone finding your cat can hopefully help it be reunited it with you.
Have a look here for your local branch:~
http://www.cats.org.uk/contact/findcp.asp
I know it's easier said than done,but try not to worry too much,I am sure she is fine,and will soon be back with you.