Unless you have proof or she admits it you could be charged for slander. If she actually does get fired she can sue you for lost wages as well.
The only way she would "get the sack" is if it against company policy for employees to date or be romantically linked. Otherwise it no ones business - not even yours.
I am sorry that she hurt you. Be a better person and let it go. It sounds like she is more then capable of causing her own problems