I guess you have three options with that. One, would be you could come up with your own recipe if you have brewing software (not recommended if you only have one batch under your belt. Two, you could find some other partial mash recipes for a two hearted clone on the internet, or three, just buy the kit and everything will be simplified for you.
I recommend just going with the kit since you're fairly new to brewing. I don't think you'll have access to Northern Brewer's recipe until you buy it (I'm sure a small percent of the kit sale includes them sharing their recipe, and it's usually in bad taste to post a companies recipe on-line). If you find that you you want to brew it again, you could certainly just get the ingredients separately since you'll have the recipe, but i've found that it's not that much cheaper than just buying the kit.