Hey claudia, you can use this link to check for decent rates and proximity to the airport, they too, are one of our partners in the soon to be unveiled travelport.
and we find their rates second to none, (which is why we selected them as a partner) The site you'll be going to is our US version so it's in American Dollars and includes all taxes and room charges so at least, no surprises.
http://www.octopustravel.com/enter.jsp?siteid=deskdusHit the page, and go to the pulldown list for London, Heathrow and you're all set
