I don't have a wired internet connection and I was wondering if it would be possible to install the latest version onto the SD card?
Alternatively I tried bridging my laptop's wireless connection with its wired connection but that didn't seem to work.
You can just use the standalone image, which does not require a network connection for installation, as all components are included in the image.
This is accessible from the RaspBMC download page
What you could do instead of bridging the connection is to emulate the Raspberry Pi on your laptop and boot into the image. You can then update that image before flashing it to your SD card.
There are instructions on how to emulate the Raspberry Pi using Qemu in these two questions:
Just download the full ISO form here.(offical downloads)
And burn the ISO to yur SD card (Minimum 2GB required) Look- Here is some more help.
I am not sure why and form where you got that self installing version? weird ...
Then- if you are using Windows 7 you can share your wired internet from your computer using your WiFi card in adhoc mode- (Not all WiFi supports this)
In the most extreme case- If you got an Android or iPhone- There is an option to use your 3G/HSDPA as a Hotspot for all your Wifi Devices.
But there is also a way to share your Wifi via LAN (using crossover LAN cable from Point-to-Point!)(or a switch in the middle, using 2 cables Point-Switch-Point) But you have to set static IP's all over the place.
