Need help with the 40's version of Tolkien's Gawain & the Green Knight (edited by E.V. Gordon NOT Christopher)

It's from the 40's and dumb am I was I didn't research before I bought the book, the forewords are really great and makes me want to read the book but the fact is, I can't. I don't know the old english letters (I am born in Sweden) and it's hard to know what some old words mean, there is a dictionary in the book for old english words but using that would make the reading painful, I'd have to look at it all the time! Please, any advice on how to start reading this particular kind of English. (Why couldn't Tolkien just translate the poem to modern English damnit!?)