My friend, you can drive into the city and parking at one of the many parking garages in the city. However, be prepare to pay between $20 and $30 pre night in parking.
Alternately, you can park in Jersey City or Hoboken, NJ and take the PATH train, which is a commuter rail line, into the city. The fare on the PATH train is $2 pre trip.
There are plenty of parking garages in both JC and Hoboken, therefore, I would recommend looking up for parking garages on any search websites.
Now, with regards to the Beacon Theater. The theater is located on Broadway and West 74th Street on Manhattan's Upper West Side. You can take the 1, 2 or 3 subway line, which is the red line on the subway map at the link below, to 72nd Street.
Once at 72nd Street, walk blocks north along Broadway from the subway station to the theater as indicated on the map at the link below.
The fare on the subway is only $2.25 one way with a pay-per ride (regular fare) MetroCard or $2.50 with a SingleRide ticket.
I hope this infomration is very helpful.
Good luck and enjoy the concert
Native New Yorker