Extending my wireless network range

[unwired]

Hope you guys can assist with this.

I have and (old) Telkom Premium Combo Wireless Modem/Router attached to my desktop.
when working from home, I switch on the wireless on my laptop and are able to access the internet from one bedroom - though the connection is not good.

When I try to access from another bedroom, the signal is almost non-existent. This room is further away and separated from the computer room by a distance of +- 20m with lots of brick walling separating it.

How do I boost the signal that I get in both bedrooms - get a new modem/router or just a new router? and where does an access point fit into all of this?

Thanks

 

[ponder]

Use 802.11n capable devices to extend range or look into high-gain antennas.

 

[unwired]

Use 802.11n capable devices to extend range or look into high-gain antennas.

is that an access point?