What can I say but to thank you all once again. My brief (and ongoing) trip into the world of wireless networking has been interesting if sometimes a little frustrating so far. A couple of the people at work are lending me bits of kit (including some of the stuff recommended above) so I'll get to try some alternatives for free.
Next thing to do is replace the old Dell though - it struggled to play the Spider Man 2 movie trailler (over Real 10) compared to my shiny new HP (unfortunately technically not mine to abuse

)