Hi
I am not expert ...
I am not British citizen and applied divorce my husband who is British.
First of all, please try to find nearest CAB (Citizens Advice Bereau)
http://www.nacab.org.uk/index/getadvice.htm#searchboxto ask if you can take legal aid or not.
To visit there, sometimes you have to wait at reception for AGES...so be aware...but some CAB office can take appointment, so anyway, have a look and check the web site where is the nearest CAB from your home.
To ask CAB is free of charge.
It will be ideal to bring your passport if you have got residential visa to stay in the UK. To take legal aid ,it depends on your income, savings etc. But in your case (and my case as well) they check our visa status if it is ok to take any benefit or not.
I hope it will help you...but there are lots of people who support you...(I have been helped lots by lots of people here..so that I can survive...) so don't worry.
moca x