Airport Express Hacked (ish)

Well I have found a major flaw in airport express. Heres the story (try not to laugh).

I recently moved to Switzerland and my appartment comes with a hard wired internet connection. I have an iphone and an ipad but no actual laptop (I used my mums before I moved and now I just sync when I visit her in the UK).

Obviously a hardwired connection is pretty useless for me, but luckily a neighbour somehwere (I live in a block of appartments so no idea who was) had unsecured wifi, so being the pikey that I am I "borrowed it".

A few weeks later the wifi network disappeared (i.e. was no longer listed, not just that they had secured it).

So begrudgingly 2 weeks later when I got paid I went out and bought an airport express. I plugged it in at the mains and put the hardwired internet cable in the back, but due to the lack of actual laptop I couldnt set it up properly. Luckily I found that it still gives out an unsecured signal before its been set up (it flashes amber but it still works) so I could still use it.

My new wifi has the exact same wifi name as the neighbours old unsecured wireless network (I know its mine as I tested it, plugging and unplugging it), so I could only assume they had an airport express as well and either lost or broke it.

This was later confirmed when my airport express light suddenly switched to unflashing green and I got booted off the wifi only to discover that neighbour had completely outpikeyed me and used their installation disk to connect to my airport express and secure it, thus locking me out of my own wifi! Cheeky B*gger!

Karma has bitten me on the bum! I reset the router which unlocked it and unsecured the wireless but then the neighbours just resecured it grrr (at which point I unplugged it completely and gave up for the night)

My boyfriend has a work laptop so he has asked IT to install the software from the disk (he didn't have permission to install anything before), which they've done. So we're going to try securing it ourselves tonight using his work laptop.

Does anyone have any idea if there is a way to stop our neighbours from being able to secure our router before us (and when we have got it secured I want to know if they will be able to reset it remotely at all). Also I'm a bit worried that if they find/fix/get another airport express router themselves that we might have problems with our signals getting mixed up.

I know its an express router but surely it shouldnt be this easy for someone else who has airport to secure someone elses devise???

Thanks!