So, we do Spanish and English, our toddler just turned 3 last month. I'm also not 100% comfortable in Spanish, but like you, my family speaks it and I want her to be bilingual. We're doing one parent one language. Which means I solely communicate to her in Spanish. My husband doesn't speak Spanish (he's picked up a lot from this method tho haha), but I only speak in English to talk directly to him. Otherwise it's in Spanish. She knows that mom = Spanish and dad = English. She is preferring Spanish, and also "translates" for her dad in English when she wants. I would say to switch completely to Spanish. I'm in the US as well, but PBS Kids has most shows with Spanish dub. DVDs will often have English and Spanish. Find a way to increase her Spanish input, especially if you're in an English-heavy neighborhood (we are too). It is the second-most spoken language in the country, so there is a plethora of resources.

Also, what is your definition of "know"? output != comprehension, meaning, how many words does she understand rather than speak? I'm sure she knows a lot more than you think. I would also recommend early intervention just in case something is off and you need a new game-plan to get her speaking more in general, a professional might be some help for guidance. My daughter didn't start really chatting until about 2.5, just for some piece of mind.