As a former cop I can tell you that there are many sides to every story. The statement attributed to a LEO (Law Enforcement Officer) that they could do nothing without observing it is weak. If an offense is alleged and a suspect identified and the very least it should be investigated. If witnesses have made statements and they jive it should establish "probable cause".
An investigator makes out an affidavit stating what he found out from the investigation, presents it to your prosecutor (could be a city attorney, county or district attorney). If it passes their review it goes to a judge for issuance of a warrant. The LEO's in the city can arrest the assault suspect or it can be the Sheriff of the county. State Patrol normally sticks with traffic related work unless they happen to stop the guy for an infraction and run him--finding the warrant.
States used to have a procedure to force officials to do their job. It is called a remedial writ called a Writ of Mandamus. You will need an attorney to prepare it for you, file it with the court and get the police department served. Many states have put that on the back burner and require you to go through adopted Rules of Civil Procedure. You might find some legal references at your local library. Often titled as Court Rules or split into two books with one called (Your State) Revised Statutes. These are usually posted online as well.
If you arn't good with details, know nothing how the law works, or have no access to a computer you might see if there isn't a "Legal Aid" organization to help you. Criminal actions can't be "good enough for government work". You need to tell every detail of the event because a persons freedom may be at stake. False reporting is serious. If the guy violated a restraining order he should be taken into custody and let the judge deal with it.
Don't believe the limited resources viewpoint if you are being assaulted and if you have a history (possibly intimate) with the alleged assaulter then other laws can come into play like domestic violence. There are many different lesser crimes that could apply that don't even require physical confrontation. Stalking, harrassment, disorderly conduct are just a few before assault & battery takes place.
Personally I carry a .45 auto with me at all times. Of course I know how to use it (or not). I have a CCW permit. Maybe you and your friends are viewed as gangbangers or troublemakers by the PD in a college town. I worked in one and we found nonstudents took more of our time. Forget about suing for money and try suing for action.
I found that when I was a detective the reporters (print or TV) wanted me to give them a story all of the time. Get copies of the reports made about the incident, copies of witness statements, determine if an investigation is active (they won't give you copies of records if it is) and then contact the media. You won't make any friends of the boys in blue but will probably find other with similar experiences. So get the city council to cut back funding because they need to layoff cops that are just feeding at the public feedbin. Fun Huh?