Well, you have oz/c, so you just need to step it up to what gravity one pound will get you in one gallon of water. Running the numbers real quickly, based on the data you gave, I get a potential of 1.0343.
I hope someone checks me out on that. It is Friday afternoon, after all.
By the way, that agave nectar does add some nice agave flavor.
Beer is good for anything from hot dogs to heartache.
Drinking Frog Brewery, est. 1993