Just out of curiosity, were you able to get a native speaker to do the audio? It sounds like it, but sometimes I feel like her enunciation could be clearer. This sentence really sounds to me like she is actually saying vagyunk, the only reason why I know it is vagyok is because we haven't learned vagyunk yet in the course.
I am not a native speaker, and am still very much learning basics. That said, I think it's because the whole sentence is "Itt vagyok fent." -- "Here I am above". I think because nothing is between vagyok and fent to show above what "I" is, that it means upstairs, and 'on the top' would need be expressed like "Itt vagyok a ház tetején." -- "I am up here on top of the house."
To say that, I believe you would use fölött instead of fent. It is a bit hard to explain, but the way I understand it is, with fent, you aren't doing anything in relation to anything else, you are just there. With the original sentence you are emphasizing more HERE I AM, above. So, the "above" is sort of disconnected. In your sentence "above" is in relation to "here" and is connected with it, so it would be fölött. At least, I'm pretty certain that's the way it is, but someone can correct me if I'm wrong.
I used a literal translation. Itt= here, vagyok= I am, fent=above. Stringing it together: "Here I am above." This is good English and it carries the focus of "here" in the Hungarian. And in previous translations of "fent" "above" was rendered. Please explain why "Here I am above." is incorrect.