Oh my... that's... so slow?

Why so slow? Its only 24GB.. you can use external hard disk and it's way faster than that. 20 minutes top from PC to external hard disk and back to PC (USB 2.0).
Only 200Mbps? The spec itself is already bottleneck, going max theoretically 23MB/s so you won't fully utilize the Gigabit switch. There's some much powerful one out there, if you don't mind to spend more... well that depends on your usage.
I don't mind drilling holes and pulling cables in my home, one of my friend even want to use Cat6 cable of which is overkill, but I'll advise him again.

@Homeplug sifu out there: Is there a risk of using Homeplug when there's lightning/thunder? Because even the phone line able to fry a modem...

My experience of see-ing my own modem hit by lightning and sparks lits up the room

luckily the whole house was blackout (due to trip) before huge one hits it, otherwise my PC would have gone with it as well.

i think its the problem with the way OSX handle file transfer,when i move them one by one,its way faster