Since you already have a decent sub(You mentioned Deep Blue, I supposed it's a Helix Deep Blue, which is considered as quite decent), you can skip upgrading it.
Concentrate on getting an aftermarket HU for your setup, if not mistaken the Civic's HU doesn't have any RCA output, and also it has some weird signal response due to being EQ-ed for the cabin itself. So the first upgrade would be to get a new HU, either install another one in the console in front of the gear knob, or get the aftermarket adapter and replace the stock HU compartment. That should cost around RM1.5k roughly already depending on what HU you buy.
Can't recommend you on the component as I'm not too well versed with the component set market. If you plan to run active, might as well just get raw components.
Well.. you could re-use your amp if you only want to run front 2-way passive and sub.