Frustrating decrease in speed

[#1]

This is unlikely to be Plusnet's fault but I wonder if anyone can help?
When I plug my laptop into my router I'm getting full speed:

But from the main computer which is on the floor directly above the router, I can't get any faster than this:

I've tried both 2G and 5G networks on my Asus N66U (both of which are showing a 100% signal) and the above is what I get. I have even bought homeplugs over the powerline and am getting the same speed  
Anyone have any ideas?
Edit: here's what my wireless signal is - apparently I have a connection rate of 300 Mbps?

[#2]

You use the same TP-Link Dual Band USB Wireless n Adapter as me....if you hover your mouse over the TP-Link icon in the right corner of the task bar it'll show you the true data transfer rate.
For me it's 130Mbps...apparently that's the limitation of the Plusnet 582n router. 

[#3]

Thanks.
It says Transmit rate: 13Mbps  
I wonder if it's just a poor adapter?
dick:quote

[#4]

Quote from: Glenn

For me it's 130Mbps...apparently that's the limitation of the Plusnet 582n router.

It's a limitation of what the router is configured for by default: http://npr.me.uk/telnet.html#w300

[#5]

Quote

When I plug my laptop into my router I'm getting full speed

Quote

But from the main computer which is on the floor directly above the router, I can't get any faster than this:

Have you elimated the main computer as the culprit by trying the laptop from the same position ? and then trying the laptop with the USB adapter to eliminate that ?

[#6]

Quote

Have you elimated the main computer as the culprit by trying the laptop from the same position ? and then trying the laptop with the USB adapter to eliminate that ?

That sounds like the best plan so far to me