Help on gta 4 please?

ok so i completed the game. [dont like my outcome btw] i remembered on the other gtas how you could buy your own houses when you please. but can you do that i this one? also.. when i was first able to get on the internet.. i tried dating all the chicks but they all gave me negative feedback.. then i got to a certain point where i could accually date them.. but the only 2 i could date where carmen and kiki because i hadent tried with them.. then when id go back and try to date one of the girls i tried before with, it wouldnt let me. id click the date on and itd go through, then click back and go into it again, and itd give me the option to date them again! the on didnt go away like it did with the ones i dated already. any suggestions?