Install deb packages with its dependencies manually on mac mini - Broadcom firmware

Hi, I installed ubuntu server on a mac mini late 2012, and I have now (as expected) a problem with the firmware for the Broadcom network adapter / wifi card.

I could install those firmware quite easily with the package firmware-b43-installer but I obviously cannot use apt to download and install this package.

Then I thought to manually download the package from another computer and install it manually in Ubuntu. I saved the .deb into a USB stick and tried to install it, but this package depends on other packages that are not installed on the machine.

Then I thought "ok, I'll do the same for the dependencies and I will install the manually before install the firmware-b43-installer".

The problem is, of course, that also those packages depends on something else.

I don't think is a good idea to go down into the dependency hole and look manually for all the depndendencies of the dependencies... there is a more efficient way to do this? There is a way to download a package with its recursive dependencies?

Or somebody installed already Ubuntu (or a debian based distro) on a mac mini with Broadcom chip that can put me on the right direction?

Thanks a lot.