Over the years I have seen many computer/printer repair shops come and go. The ones that survive usually have a brand attached to them, meaning they are the official dealer.
I think you need to study the local market. Just because you know what your doing, doesn't mean you will get your foot in the door to big companies. It just does not work like that here, it's all about who you know, not what. This is the #1 reason I see many "gringo" businesses fail.
Good luck and feel free to post any questions you have here.