Router as repeater

Here's my setup. A PC downstairs, hard wired to a wifi modem/router.
I got a new PC for upstairs.
The main router is a actiontech m1424wr rev 1.
The usb adaptor for the PC upstairs is a netgear n150 wna1100.

A Netgear n150 wnr1000 is going to be the repeater.
Instead of running 50 feet of cable, I decided to do it wireless.

The new PC is getting 65Mbps. My tablet, when I use it upstairs. I get anywhere between 5-65 Mbps. When I use the tablet downstairs, I get 65Mbps.

For me 65Mbps is good enough for HD video on the desktop. I don't notice any difference from the PC downstairs, which is getting 100Mbps.

But on the tablet, I get lots of signal dropping when I'm upstairs. But not downstairs.

Why is the tablet getting a weaker signal then the PC?

If I do decide to run wire. I just plug it form the lan on the main router, and plug that into the lan or wan on the repeater?
Then from the repeater I'll just use a cable from the lan, to my PC. Then
Do I just replicate the ssid and wpa from the main router, to the repeater?

In case anything happens, I want to switch seemlessly beteween them.

I'm with Verizon fios. Fios faq, and support is crap. The only thing they talk about how to extend the network, is with MOCA.
But I don't want to do that. According to them, I would lose ondemand, and the channel guide.