I have the TL-WPA4220 with the TL-PA4010, I need to add a new extender. I understand they come in pairs. Can I buy the new AV1000 Gigabit extenders?

What about the speed? 

Ideally, I need a passthrough connection (no wifi) to a computer in a room upstairs, (fastest possible) and a WiFi extender for the patio. The WiFi in the patio is only to browse the internet and stream music. 

What would you recommend I should buy and what would be the best way to connect it?

Thanks,