This is what my buddy, Binni had to say:
Fortíð tveir dagur
Fortíð = Past tense, not as in the past few days. For that it is Síðasti (singular) and what belongs there Síðustu (plural) Fortóð = The past or my past or past tense
Hér eru tveir
um tvo x
frá tveimur
til tveggja :)
Hér eru dagar (Here are days)
Um daga (About days) x
Frá dögum (from days)
Til daga (to days)
In the sentence your talking about days, not something particular like looking forward to them or coming away from them or speaking about them in a "pointy manner" HERE ARE DAYS etc
Hér eru síðustu tveir dagar - Here are the past two days (pointing at an almanac or something, I dunno.)
Síðustu tvo daga! in the past two days
Á síðustu tveimur dögum - In the past two days, awkward by itself, but works when you add some verb, like Á síðustu tveimur dögum hef ég reynt við margar gellur - In the past two days I've hit on many women.
Mér er hugsað til daganna tveggja í sumar þar sem var hlýtt - I'm thinking of the two days of summer where it was warm.
:D
