If you start getting a lot of designs, might be worth your while to invest in a portable hard drive, that connects to your computer. That way you can put all your designs on that and what you want to work on transfer that one on to a USB stick. Most sewing machines don't like big memory sticks. I was told not to use any bigger than a 2GB. There are a lot of embroidery sites, that you can download them from that site to your computer. You need to set up a file for them.
I have all of my designs set up in folders. Like all butterflies, or cats or what ever so I can find them. As I need them at that point I put them on my memory stick. You will find out that you have a lot more designs than you can fit on a memory stick. I have a few 2 gb memory sticks that I use only for my embroidery machine. I don't know if you have Wal-Marts where you are, but they sell them. Most of the Office Max and Office Depots, don't go with the smaller memory sticks. Not sure what you have in the UK.
If you need anymore help just PM me. I must have 500 or 600 or so by now and there is no way they will fit on a 2 GB stick. This way with the portable hard drive even if your computer dies, you will not loose them. The type I have is an Iomega EGO, love it. I purchased a Western Digital and I can't find anything on that, it backs up everything on the computer, but heaven help you if you ever had to find it, but that is about all that does.
All you have to do to download from most sites in pick what your font type is like "PES", then they will download it in a zip file to your Email. If you don't have a way to zip or unzip your files, then go on your computer and download the free unzip file. You can zip or unzip all your files.
There is always someone out here on this site that can help you, that was the way I learned how to do it, from help on here.