Yo tambien tengo un portatil de Acer, un pelin mas antiguo que el tuyo, el mio tiene una ATI 9700, pero este tutorial bale para todas las ATI's y a mi me funciona perfectamente.

How to install Beryl (ATI)

• Read: #General Notes
• Reference:ubuntuforums.org

"All credit is due to the forum user in the reference link above. This is been added to this wiki so that other users will not (hopefully) have to search for a solution. This has been tested on the i386 version of Feisty Fawn. Someone, please modify this if the AMD64 version is also compatible."

• Open a terminal:

Applications > Accessories > Terminals

• Verify our system is up-to-date:

sudo apt-get update
sudo apt-get upgrade

• Install Xgl (This is the main problem with ATI cards. The fglrx driver will not support the built-in Compiz feature in Ubuntu and we need Xgl to run our new version of Beryl with an ATI card.):

sudo apt-get install xserver-xgl

• Write a script so Xgl can start on its own:

sudo gedit /usr/local/bin/startxgl.sh

• Enter and save this script information:

#!/bin/sh
Xgl :1 -fullscreen -ac -accel xv:pbuffer -accel glx:pbuffer &
DISPLAY=:1
cookie="$(xauth -i nextract - :0 | cut -d ' ' -f 9)"
xauth -i add :1 . "$cookie"
exec dbus-launch --exit-with-session gnome-session

• Make the script executable:

sudo chmod a+x /usr/local/bin/startxgl.sh

• Now, we need to put in a Xgl option in our GDM login screen:

sudo gedit /usr/share/xsessions/xgl.desktop

• Enter and save this script information:

[Desktop Entry]
Encoding=UTF-8
Name=GNOME with XGL
Comment=
Exec=/usr/local/bin/startxgl.sh
Icon=
Type=Application

• Also make this script executable:

sudo chmod a+x /usr/share/xsessions/xgl.desktop

• Disable the universe repositories (these provide Beryl software that is incompatible with the fglrx driver).

Go to System > Administration > Software Sources 
Uncheck Community-maintained Open Source software (universe)
Click Close

Back in our terminal:

• Add the correct repository key:

sudo wget http://ubuntu.beryl-project.org/root@lupine.me.uk.gpg -O- | sudo apt-key add -

• Add the correct repository to the top of your apt source list:

sudo gedit /etc/apt/sources.list
Enter: deb http://ubuntu.beryl-project.org/ feisty main
Save and close gedit

• Update your apt sources:

sudo apt-get update

• Install the correct Beryl applications:

sudo apt-get install beryl emerald-themes

Apt should retrieve all of the dependencies such as plug-ins and libraries

• Install your ATI drivers (if needed):

Go to System > Administration > Restricted Drivers Manager
Check the Enable check box for your ATI graphics card

You will need to reboot to enable the card.

• After a reboot and choosing Xgl from your sessions list at your login screen, test Beryl. In a terminal:

beryl-manager
emerald --replace

http://ubuntuguide.org/wiki/Ubuntu:Feisty#How_to_install_Beryl_.28ATI.29

Un Saludo. "La única iglesia que ilumina es la que arde"