Does your electric pump have a battery pack? That might be a better option, since a hand pump can be not as effective. Your $ might be better spent on batteries. If not, Medela and Ameda make comparable hand pumps.
Oh my gosh, I know exactly what you need, hon. I went camping this past summer and used the medela harmony manual breast pump and it was perfect for this. It's very cheap too, only about $30 online where I bought it. I love it!