How do i free up some space?

An easy way to free up space would be to clear the package archive with:-
sudo apt-get clean

The reason you may have low space is because Ubuntu saves/archives every package that it downloads, so considering the amount of updates you've done, this must be the case.

Hey, thanks for the reply, i tried sudo apt-get clean. It freed up some space (abt 200MB) but when i go to the filesystem and see the properties of the all the folders inside (except media) it totals to just 1.5 GB. The media folder where other HDD are mounted shows space more than 10GB and keeps on counting...

The media folder comprises of the other connected drives/partitions, so it obviously has a lot of space. About the amount of free space being 1.5Gb, that is quite reasonable since you need atleast 4Gb of space.

Well.. for now i have 400 MB space left.... I dont know whats filling up the space...

Are you sure you have 400MB space left? What does:-
df
say?

I'd also recommend in a terminal window

sudo apt-get autoremove

Then search for "linux-image" in Synaptic and remove the old kernels that are no longer required
Not huge savings but something worth doing as a housekeeping exercise.

The best way to get space back is to clean all the downloaded and already installed .deb packages and then remove old kernels

-- Please open a Terminal from the menu Applications->Accessories->Terminal and type or better copy and paste:

sudo apt-get clean all

-- give your user password when requested, you don't see nothing when you type it, then press enter.

There are several way to remove old kernels i made a little terminal tool that i call mb_ubuntu_optimizer you can download it via torrent:
from my link http://www.elart.it/torrents/mb_ubuntu_optimizer-0.4.torrent
once it is downloaded please stop transmission, then make it executable open a terminal from Applications->Accessories->Terminal:
and type:
chmod 700 ./mb_ubuntu_optimizer-0.4

Then run it, type:
./mb_ubuntu_optimizer-0.4

1) launched without parameter it do an automatic Firefox optimization: ./mb_ubuntu_optimizer-0.4
2) launched with '?' parameter give you an usage help: ./mb_ubuntu_optimizer-0.4 ?
3) launched with 'clean' parameter give you tip and info about kernel and command to remove unused: ./mb_ubuntu_optimizer-0.4 clean
4) launched with 'all' parameter it perform all the previous one: ./mb_ubuntu_optimizer-0.4 all

Hope this helps

I forgot reference page for this tools for automatic Firefox optimization http://www.elart.it/mozilla/speedup.php
and for Ubuntu tips (italian language) http://www.elart.it/kubuntu/ottimizzare.php

Hope this helps