Can I upgrade my early 2011 macbook pro wifi to 802.11ac?

Possibly, but it would most likely be via an external USB wireless adapter to do so. I would suggest checking out OWC to see if they have what you are looking for.

There is a company selling internal wireless AC replacements.. I came across them searching for something.

http://www.quickertek.com/products/Ucard.html

$149US is not cheap.. but the problem is Apple seem reluctant to have a standard.. I mean if there was a standard any Tom Dick or Harry could replace their wireless card.. so every couple of models they completely change the interface.. why.. to prevent people updating their own computers is about the only easy conclusion I can come to..

So this crowd had to get cards specially made to mimic later ones, but use older interface so the price is very reasonable.

Of course is it worth it.. ?? I have a 2011 MBP .. totally awesome machine.. and it can do 450mbit link with any recent 3 stream N wireless router.. and are you going to get significantly faster speed.. when you have the best port on the planet.. gigabit.. to get real speed.. I think NOT.

If you desperately need AC wireless.. you can buy an AC router.. and pair it with your existing AC wireless router and use it from the MBP with ethernet.

So one of those routers could be a Time Capsule..

I had to find some way since it doesn't seem like the question is highly relevant to a discussion area about Time Capsules.