Hello I have a question regarding settting up a wireless network

I currently have a DLINK DIR-625 WLAN Router hook to my cox cable modem.
That router is in another room

Now I have a 2 PCS,PS3 in another room downstairs
I don't want to run any wires from up stairs to downstairs.
As for the Pcs currently they don't have any wlan devices.
I want all them to access the internet using a central unit such as another wireless router and use short cables since they are very close to each other.

I'm confused about if I should use a bridge or access point.
I read about an access point,but to me it sounds like I still have to run a cable from the access point to the main router. Is this correct?
Also can any router be turned into an access point even though it isn't mention?
I've read about the bridge mode,but unsure if that is exactly what I need.

I'm very confused with networking,it's like being a blind octopus trying to wrap presents.
One more question,can anyone recommend a good site or book to learn networking?