I am experiencing a problem with reducing the brightness. I own a Acer S5 ultrabook i7 and i recently ubuntu in it. Ubuntu is the only OS runnung. Also, i am having some trouble with the wifi as it keeps disconnecting automatically. Please Help

Description: Ubuntu 12.04.1 LTS
Release: 12.04

I am unable to reduce the brightness of my labtop.

Also, the wifi keeps getting disconnected.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: acpi (not installed)
ProcVersionSignature: Ubuntu 3.2.0-34.53-generic 3.2.33
Uname: Linux 3.2.0-34-generic x86_64
ApportVersion: 2.0.1-0ubuntu15
Architecture: amd64
Date: Mon Dec 3 03:25:53 2012
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: acpi
UpgradeStatus: No upgrade log present (probably fresh install)