Does anyone know of a gadget that can ‘magnify’ the wifi signal I receive at place like truck parks etc so I can get a better reception on my iPad?
Maplin’s sell them about £15-£20
It might help more if you had an external antenna on your wireless, however it is difficult to take that route if you don’t have the attachment. I think they’re called ‘high gain’ antennas, but they can be pricey…
No good for an ipad but this works wonders with a laptop and a wifi dongle
You should sell that 
This is what I’ve used on my car roof in the past when people didn’t bother much about home router security:
mobilemark.com/shop/item.asp … &catid=657
USB plug on the other end straight into your laptop and voila! Works extremely well and I was usually spoilt for choice as far as connections went.
You want to be careful on the gain btw - too much and they won’t work.