Current Mirror Gain 1.5 with discrete components
I simulated your circuit in LT Spice and got a ratio of 1.79.  You only need 2 transistors for this circuit, so I revised the circuit using only 2 transistors but put resistors between emitter and ground. (I kept the 1k resistor in Q2.)  So referring to your circuit, eliminate Q1, Q4, and Q5.  Place a 30 ohm resistor between emitter of Q2 and ground and a 20 ohm between emitter of Q3 and ground.  I now simulate a ratio of 1.5. As I decreased the 30 and 20 ohm resistors it diverged from the current ratio of 1.5.  If you change the collector resistor from 1k you will have to make adjustments in the emitter resistor.  When building this circuit with real transistors you may need to do some trimming.