Call the police and ask what is happening with the case. You have very little say whether it goes to trial or not. The police will forward the case to the DA if they feel there is a case there, and the DA will decide if charges are appropriate.
Frankly, you should have left the moment he said to leave. But, instead, you stayed, struggled over the hammer, and continued to put your girlfriend on your back. Why didn't you leave when you said you were? To me, it doesn't seem worth angering a potentially unstable fellow just so your girl can ride on your back.
Is there a case for assault with a deadly weapon? Sure. But I'm going to wager that the other guy is going to have a different account that might include your making threats to him, possibly that he believed you were trying to break in, etc.
Call the police department and speak to someone who knows about the case and see what is happening with it. You can also hire an attorney and sue the fellow for damages .. provided he has enough money and assets to pay for the attorney and for any award you might receive.
- Carl

