I think you will probably need to either call the airline or use a travel agent to book the “open return” ticket, anyway, so I’d do that for the whole package.  This is the type of thing where a travel agent might actually save you some money and/or find better connections and options than you can find by yourself — just price the tickets and find the best connections on expedia or orbitz so you can judge whether the travel agent is getting a good deal for you.

My fears have come true my friend. I have to go to a travel agent. That means i lose a whole day today.