Time Capsule - Newbie Question Wifi Question

Hi Guys,

i am using since a year Apple and i am very happy about the quality of my Life. Really a pleasure working with those great products.

At home i have a very weak Wifi Signale and i want to improve that. If i would buy a Time Capsule and join an existing Network to create my own Network, would that improve the wifi signale?

With a Wifi Strength App, i could messure, that i have at one spot in my appartment with a good signale. I could place the TC there and create a new WiFi Net.

Thoughts? Experience?

btw. I am also getting the Apple TV, is there any guide how to sync it all? I wish the TC had speaker out, that would be great. But you can bridge that through apple tv, if you good TV speakers, correct?

Thanks Guys, Alper