Electrical – NPN driving PNP, Diode from NPN Base to PNP Collector

You could use an emitter follower and drive it from a 5V input. It will drop one Vbe drop, about 0.7V, so the power dissipation at 150mA would be about 100mW, which should be okay for most transistors over a reasonable temperature range. Use a pull-up resistor on the base if you don't have something like an HCMOS driver.

^{simulate this circuit – Schematic created using CircuitLab}

The 100R base resistor is sort-of optional, but in some cases the emitter follower can oscillate at VHF frequencies if you give a really stiff base voltage, and the resistor will prevent that.

It's not clear why you have chosen a PNP transistor to begin with - I assume it's because you had to start with something. Throw it in the bin; get some MOSFETs, Darlington transistors or beefy NPN transistors (in order of current-conducting capacity, highest to lowest, generally speaking).

The following diagram uses IRF510 MOSFETs, which are standard off-the-shelf types and are sold on all manner of hobby electronics sites in one form or another - maybe IRF540 or 530 instead. It can handle currents of 4A or more (read the datasheet!) and requires very little in the way of external components, as you can see:

You don't need the 3.3V rail; it's of no use. If you can provide some specs for the 12V LED cluster (we accept datasheets or cold, hard numbers) then somebody can suggest a suitable device to drive it if you have trouble sourcing certain components.

EDIT:

In the Falstad circuit you had the forward voltage of the LEDs too low (11V). That simulator is very basic at best, and so was only dropping 11V across the diode leaving 1V at the gate of the second MOSFET. The emmended can be viewed here.