Huh? What you mean by focusing limited.. you mean its focal length is not wide enough? If so, then what you need is simply a wide angle lens and in this forum, the popular ones are Canon 10-22, Tamron 11-16 f/2.8 and Sigma 10-20 / 12-24. Be ready to spend at least about $800 and above. You can find the latest prices here and reviews wise, do a search in this forum and out there.
Have you tried? How do you come to that conclusion?
Wide angle lens can be useful, but only if you know how to use it. Many people are just overwhelmed by "wow, that's wide..." .. and they take pictures of lots of empty space. Use the wide end of your kit lens and take pictures of scenery. Read about composition, try to compose and capture good images with 18mm. If you can't do this with 18mm then also 10mm will not help. If unsure you can still rent the wide angle lens for a weekend. Check the "Services Offered" section.