This is a HUGE and very modern Department Store-cum-Supermarket.
Considering the fact that you are in Mongolia, a very REMOTE country, this place is actually quite well-stocked.
Everything, if you are not too demanding, seems to be available in the ground-floor supermarket floor and upper-floor department stores. Good to stock up on groceries to cook at your guesthouse or go camping.
There is no lack of Internet Cafes in Ulaanbataar. Take a walk through the city centre and you will see 10-20 of them. The prices are almost the same. We found a good one just east of Sühbaatar square (one block to the east, dont remeber the address).
This is a new and relatively modern department store by Mongolian standard worth visiting but it is not very big compared to those in big cities.