I'm building a weather station using a raspberry pi (the very first version), which collects data from an arduino and uploads it to a database on my website. Currently, a long network cable runs from the pi to the nearest ethernet socket inside the house and I'd now like to replace this with a wireless/wi-fi antenna. Everything (both the pi and arduino) is outside, in a weatherproof box approximately 4.5 metres from the house. Despite the weaker connection outside, I've tested it with my phone and can load websites, including my one containing the data, so it is strong enough to send the tiny pieces of data that I have.
I'm looking for a cheap/reasonably cheap antenna to allow me to connect to the wi-fi network and upload data. It MUST be water/weatherproof because it will be mounted a few metres up the pole of my station. Therefore, it also needs to have a couple of metres of cable and connect via USB (assuming this is the port used for devices like this) to my pi in as simple a way as possible. It doesn't have to be big and bulky or anything, just waterproof.
I'd love it if anyone knows of an antenna that would work for me.