Wireless DSL connection for RJ45 ethernet port

Hi folks,

Would anyone know how I could connect my desktop PC's ethernet card
which has an RJ45 connection to a wireless broadband DSL network?

At the moment my PC is upstairs yet my phone connection is downstairs
and I want to get rid of that cable going up the stairs from the
hallway. It doesn't look that great when people call around at
Christmas. At any rate I would like to move the PC into the
kitchen/dining area at home but without the cables on the floor. From
reading various vendor websites I see that I can buy routers,
firewalls and dsl modems all in one. They all, however, work
wirelessly with USB ports which my computer does not have.

I see a number of USB-ethernet adapters but I am just unsure whether
they can plug into my PC's RJ45 ethernet connection. Again all these
adapters talk about connecting to the PC's USB port. So I'm wondering
would they work in reverse whereby the wireless DSL 'antenna' has a
USB port which plugs into this USB-adapter and the adapter in turn
plugs into the RJ45 port of the PC's ethernet card.

All suggestions more than welcome.

Kind regards,
Michael