Part selection for high-side switch
Chose a MOSFET that can carry the current you need at a low enough RDS_ON at your load current so it does not dissipate more heat than is acceptable to you.

Note: You need to use the \$I^2 * R_{DS_{ON}}\$ equation to calculate the power dissipated.

The MOSFET should also be capable of being switched as full to on as possible at 4.7V Vgs. That is Vgs MAX should be closer to +-5V not +-20V. Obviously it also need to hold off the supply voltage.

Once your MOSFET is selected figure out the wattage it will dissipate. From that you can decide if you need extra heat sinking, or a better part.

Q1 can be any general purpose NPN. R values look OK.

If this is for a battery operated project I'd increase both resistors by at least a factor of 10 if you do not need to run this at a high frequency. You may also want to consider using a small signal N-MOSFET for Q1 instead.