It doesn't take too long to replace, but like you I spent hours mucking around with it before I found out I need a set of circlip pliers.
I picked mine up from supercheap I think for $20 or so. I got a set with interchangeable tips so you can use it for other types of circlips too. Cheapest I have seen, and all the others just do one type of circlip so you have to pay $120+ for a full set.
It is a bitch to do though, I might just pay someone to replace it next time.