The spectrum from stars follows the black-body curves which wikipedia has an entry. The graph within is here tho:
http://en.wikipedia.org/wiki/Image:Blackbody-lg.png

and this shows curves where there is a steep left side and a slow falling tail on the right. The point here is that if your star is a little cooler than our sun then you would a similar amount of infra red but the UV would be significantly reduced. Being coarse about it then the top end UV frequency is determined by the star temperature.

I would think that these new colours would be seen as monochrome or possibly new colours that we cant conceive of. Its like trying to describe red to a colour blind person. How do you do it.

As an aside, I thought elves had infravision as well.