Installing Windows Through Bootcamp

So here's the deal guys. I have a mid-2010 macbook pro 13" laptop. A while ago I replaced the superdrive with another hard drive. So I have an ssd and an hdd. I also installed windows on a small partition of the ssd. Well now I'm finding that giving myself only exactly enough room was a bad idea because I don't have nearly enough space for updates. I want to delete the partition and make a newer, bigger partition in its place, then install windows on it again. The problem is I'm on vacation and I didn't bring a flash drive with me to do this. I do have an external hard drive though. My question is, can I make a small 8gb partition on my external drive to act as a flash drive to make bootable and install windows from?