Yeah, that's the point of Access Points.
The number of wireless devices it supports is kinda variable, it depends on the make of the device and also your router, cause the access point is only a bridge from wired to wireless.
http://www.misco.co.uk/categories/~1244~/Access%20Points.htm , they have some access points here, however they seem quite expensive to me
, you could also buy a wireless router for the same money
Also I found another subcategory called
Wireless Ethernet Bridge, now I'm not sure what the difference between an Access point and a Wireless Ethernet Bridge is, but again they all seem quite expensive
If you look at this
Linksys WRT54G Wireless Router and one of those Access Points or Wireless Ethernet Bridges you see that this Linksys router is even cheaper...
But as you said your mother needs the router for her work so maybe you need a separate Access Point/Wireless Ethernet Bridge.
Buy anyway, it's your decision
. I just gave you a lot of info to think about