Hi Anouja. If you don't mind secondhand, there's one on dubizzle for 80dhs..
[url=http://dubai.dubizzle.com/classified/baby-items/safety-health/other/2013/4/15/maternity-bump-belt-from-mothercare-2/?back=ZHViYWkuZHViaXp6bGUuY29tL2NsYXNzaWZpZWQvYmFieS1pdGVtcy8%2Fc2l0ZT0yJnM9Q0wmcmM9MTgyJmMxPS0tJnByaWNlX19ndGU9JnByaWNlX19sdGU9JmtleXdvcmRzPWJlbHQmaXNfYmFzaWNfc2VhcmNoX3dpZGdldD0wJmlzX3NlYXJjaD0xJnBsYWNlc19faWRfX2luPVN0YXJ0K3R5cGluZytoZXJlJnBsYWNlc19faWRfX2luPSZhZGRlZF9fZ3RlPSZhZ2VfX2x0ZT0mY29uZGl0aW9uX19ndGU9JnVzYWdlX19sdGU9&pos=5'>link[/url'>
If you mean a seatbelt adjuster to keep the lap belt under the bump instead of across, you can find those at mothercare, maybe even babyshop. I had one with my last pregnancy and thought it was a good thing to have, plenty of women don't have one and do fine, but I just felt better driving with the seatbelt out of the way. I don't know if it will really make a big difference in the event of a crash, but I surely found it helpfull for the situations in between were you need to break suddenly.
Like Mrs_B said, you don't need a specific belt for pregnancy although some people like to use them.
There is some info on belts during pregnancy [url=http://www.babycenter.com/404_is-it-safe-to-use-a-seat-belt-during-pregnancy_7239.bc'>here[/url'>
I don't think you need a specific seatbelt for pregnant ladies? I am pregnant, currently have a 45 inch waist and the standard car seatbelt fits me fine. You place it under your bump not around it....