Joomla - Localisation. Change content / Redirect Users based on Location.

Hi, We have a Joomla 1.5 site. We have customers in the U.S and the U.K. We'd like to show a U.S specific site to our U.S customers and a U.K focused site to our U.K customers. I'd like someone to help us configure the site for this. Please discuss the options (ie. user selected re-direction page / automatic geo detection and redirect based on geo IP / content change by use of Joomla module or redirect to sub-site... etc.) We have complete control of the server and are happy to purchase and install a 3rd party Joomla component and you customise it. I'd prefer to have someone that's done this before if possible. If not, then someone that knows Joomla well. We run the server, installed Joomla, customised it etc. so we know our way around. We're not looking for an agency to charge huge money for this. It's really just if there's an expert out there that can get it done quickly and wants a quick easy job. Not expecting you to create all the content... just to set it up and show us how to use it.