Here's the basic progression in C. I typically capo it for different keys but I think 
in C sounds most like the original. Lovely song though.

Intro: C G Am F

(Progression 1:)
C                       G
It was a moment for the books
             Am
The calendar looked
              F
just like the novels we had only skimmed through.
C                    G                          Am
So I circled out the dates that I'll skillfully waste.
    F
For now that's going to have to do.

(Progression 1:)
C                           G                          Am
It was the brightest summer day, after we swam in the lake,
         F
that you told me our luck is gonna end.
C                  G                              Am
So we better be concerned. We're where the subway turns.
          F
We need a camera and some cash to spend.

(Progression 2:)
Dm                  G      Am                   C
And our picturesque blame; we'll put it in IKEA-frames.
Dm                        G
Up on the wall it looks profound,
               Am                     F
and reminds us Oslo is a small, small town. (Yeah)

(Progression 1:)
So it's night and we dive into a basement that's alive
with stupidity that melts into pairs.
But your good intent was clear when you split and left me here
to regret I left my high horse upstairs.

(Progression 2:)
And with the way I say goodbye
I could have ruined everything.
But I'll be seeing you around
because Oslo is a small, small town.

(Progression 2:)
I'm keeping myself calm
if just for the sake of staying warm.
So with my eyes fixed on the ground
I admitted Oslo is a small, small town. (Yeah)