most basic garaband question ever .. chords ...

I just got my macbook pro, and when I read the garageband 08 reviews , I just drooled over the idea of creating music so easily . I´m too far from being an accomplished musician, in fact all I can do is play some piano and guitar chords, fairly good enough to play the most simple rock songs.
I have been trying for several hours to create a version of my favorite songs, starting from scratch and using the loops. The problem I am facing is so basic, it might make you guys laugh, but I haven´t been able to find an answer in any forum, or in the manual.

For example, let´s use U2´s “With or without you” to present my problem to you. The songs basic chords are “ D - A- Bminor – G” . I set the main chord as “D” and insert a basic bass loop… but when I have to move to A, I have to do this complicated movement, counting the seminotes from D to A , and manually pitching –5 to get to my second chord (A).

First question is .. Is this the only way to pitch a section of the song from one chord to another ? If this is so, Garageband is far from what I expected.

Second question … In case the former question is answered “yes, that´s the only way to pitch ..” .. how do we get to MINOR chords ? --

I must recognize I´m not too much of a manual reader, I´ve just been reading the titles pretty fast so far .. maybe the anwer is out there, but it is kinda hidden for being such a basic issue for creating the music.