Have no idea whether you can get an offer in US. I am not in this area.
Just assume you got an offer in US. Your employer needs to sponsor your H1-B visa. You got your master in UK. Your only only filed your application in that normal catagory (only 65,000 people annually). Application starts in April every year, and visa will be effective on Oct. 1 at the same year. According to this year's statistics, within 4/1/07 to 4/2/07, over 130,000 filled their H1-B visa. Immigration service shut down all applications on the third day, and decided to do lottery on the applications they have already received in the first two day.
Hence, only 50% of the applicants successfully got their visas. Next year, the situation would be worse, since more F1 students are studing in US. I guess you chance to get a visa is below 50% for the following years, unless the government changed its immigration policy.