Capture the keyboard input to my application

Question

Hi all!!! i'm quite bored with a problem I can't solve. I'm doing a program which imitates the mouse, and I need that when I do "click" (double click or whatever) in another application, although the latter is actived now, I want my window to still keep the keyboard input to can handle it. I have try with SetFocus() and GetFocus() from Windows API but I can't make it works. If you could help me,it would be great;) Thanks, ciao!