i had a fight and a warrant for assault 3rd degree was issued. do i need to be booked before i get a lawyer

There are several issues at play here.  First, in the criminal justice process, it is never too early to consult with and/or retain a lawyer.  While retaining a lawyer will not guarantee that you will get the charges dropped prior to being arrested, it will at the very least facilitate the arrest and/or bond process and will further ensure that you do not do anything to incriminate yourself throughout that process.  Second, as you have learned, once the police have probable cause to arrest an individual, they have the discretion to pursue that arrest despite the request of the alleged "victim" for them not to.  Nevertheless, if your girlfriend does not wish to see you prosecuted, there are ways for your attorney to demonstrate to the prosecution that she does not wish to cooperate with the prosecution of the charges against you.  However, this must be dealt with delicately, since anything that could potentially be perceived as influencing your girlfriend involuntarily (or on your behalf) could also potentially expose you to liability for the felony of tampering with a witness.  Therefore, I highly recommend that you consult with and/or retain a criminal defense attorney to discuss the merits of the state's case, as well as your potential defenses, in the interest of obtaining the best possible resolution of these charges.