My new Galaxy S4 is plagued by Battery drainage and WiFi issues. What can I do?

I got a new Galaxy S4 and seem to have some issues with battery drain and WiFi issues.

WiFi -

I've googled around and people seem to be having WiFi issues but only with DLINK routers, my issue is kind of different. I don't have a DLINK router, i have a brand new Vodafone router. The router is in my sitting room and when I'm in that room the WiFi is fine but when i'm upstairs in my room etc the WiFi signal drops a lot and it disconnects and reconnects almost every 5 minutes. Any one ever have any issues like this?

Battery -

Only got the phone yesterday wasn't focusing much on battery life but went to bed last night charged it, woke up used the phone for around 2 hours and i'm at 49%, I downloaded a battery saver app and it said "Display" is using 78% of the battery, I presume this is the brightness, but surely 2 hours usage to half way is a bit crazy?

Anyone any thoughts?