"Here"

"Here"
 

I know that the word for here is "aqui", but what if I'm using it in this context:

Here's another invoice that you need to pay.

My guess would be:

Aquí esta otra factura que tu necesitas pagar.

Aquí está otra factura que necesitas pagar. (Note that it's not necessary to use tú.)

With the changes noted above, your translation is fine.

Another alternative: Aquí hay una factura....