I'm trying to install QGIS. (but this could apply to other applications I think)

On my other PC which has Maverick running on it Synaptic shows QGIS and all associated packages.

ON this one which is running Precise QGIS does not list. I can find it under apt-get in the terminal but not on Synaptic, Why??
I would prefer to install it via Synaptic so I can use the "force version" option.

I have the repositories and key updated so its not that.

Thanks
Veronica