Dreams aside... I'm not sure why you'd pull her over the counter. Push her back where she came from! Keep the counter between you and if she tries to jump it again give her the telephone to the face. Or.. use the telephone to her face as an incentive to get her back on the other side.
I've worked a LOT of time behind a counter and, as Guantes says, you really have to reach/jump to get over a counter to the point of being able to bite someone. You'd almost certainly be able to jump back or push her back before she got to you in real life unless you were SERIOUSLY off your game that day and she was rabbit quick.
The counter is your friend!
Of course if she jumps and you both fall on the other side then you are out of luck and it's game on.
A knife is a good option. I vividly remember the lesson in knife fighting while someone has already gotten on top of you and your knife is on your waistband. Thrust the hips up to get your attacker off balance and thrust them forward over your head, tuck your head into the attackers belly/chest so they can't hit it very well or reach your vitals (eyes, mouth, inner neck, etc), reach around or between their legs for your knife (if it's in your pocket or front of the waistband) (preferably reach around so they don't just sit back down and pin your arm but if your arms can't reach or the person has particularly big legs and you are little (like me) you just have to do what you can do), and go for disabling (tendons, muscles) or blood (arteries) cuts... stab/cut for the arteries and tendons in the legs and groin and keep hacking your way free... remember that jeans can really frustrate slashes and slashing at someone wearing jeans may result in only a shallow cut on actual flesh but jeans are no match for a stab. Stab, and start coring, pressure cutting or running (just yanking the blade up and down while continuing to thrust it in)... maximize trauma and blood loss.
If I started listing all of my disturbing "combat" related dreams I'd probably be banned or have people recommending I see a doctor or just scaring people.