Ive just looked it up on google and a length of 46cm is far too small for any species of hamster in my opionion. Just beccause dwarf's are small they need plenty of space. I find with my robo's that they use far more of their cage/toys than my syrian does.
You could always keep your eye on ebay,gumtree, market place on the forum here for a bargain. Good cages for dwarfs are zoozone 1 and 2. Ferplast kios. Barney or Alexander on zooplus due to the small bar spacing. Duna multy or maxi multy. All i can think of.
Both my robo's live alone and are perfectly happy. Chinese do best on their own but there are exceptions to this. I think all dwarf's do well on their own given plenty of attention.
My robo's eat pretty much the same as my syrian. Though some species are prone to diabetes so you would have to check this out.
Hope this helped.
Bet your hammy will love the alsaka