Plex - Buffering issues of late and WDTV question

ratedR

So my home setup at the moment is that I've got a server downstairs connected to my router that has all my media on it.
I've got an LG smart TV downstairs that's connected by WiFi and running the Plex app. Works very well, no lag or buffering but my only complaint would be that I can only play, pause and stop. No rewinding/forwarding. Everything is controllable with the tv remote.

Upstairs I have an older HDTV with no internet connectivity. I have an android tablet with Plex running on it connected to the TV via the HDMI port on the android. Using my iPhone as a remote I can control the Plex app.
This setup generally works well, but I often experience a lot of buffering. And in the past few days anything I play will play for 1 minute, buffer for 40 seconds and then repeat. Pretty unwatchable. I'm not sure if it's the android tablet (its a cheap generic brand) or the fact that I'm only using the basic version of Plex. My internet is quick (UPC 240) so I don't think that's the problem. Possibly the router? It's that absolute piece of crap Ubee EVW3226, provided by UPC.

So what I'd like to do with the non-smart TV upstairs is connect a Wireless HDD via USB. The thought would be that I could wirelessly transfer media content over to the HDD at my leisure. I don't mind if this is not that fast, I just want to avoid streaming. I could then play it back safe in the knowledge that there would be no buffering issues, and I would also have full control over rewind/forward.

Doing some research, the WDTV seems to be the only device out there that will definitely do this. I'm looking at paying at least €100 for a used one. Is this my cheapest option ? Are there other devices out there that can do the same ? Or are there any homemade options?

Cheers

degsie

Have you considered using homeplugs and an access point (AP) to improve your wireless throughput upstairs? Run a speedtest on your android tablet while next to your upstairs TV.