First of all, I recommend uninstalling Ubuntu's tex packages since have two installations of tex will only confuse things. (It is possible to keep both if you want to but you then need to be much more careful about what you are doing.)
I'm going to assume you are working with the directly installed distribution which I assume is TeX Live 2013.
I'm not familiar with these particular fonts so if anything doesn't quite fit or work, let me know.
You need to decide where to install the fonts. There are two reasonable options. The first is in your personal texmf tree. These will be available only to your user and there are some disadvantages in terms of updates to TeX Live. The second option is to install them into your local texmf tree. I would recommend this option.
If the following directories do not exist, create them [you may need to do this with sudo if you ignored the advice not to install TeX Live as root]:
/usr/local/texlive/texmf-local/fonts/type1/pctex/mt11p [pctex based on help from egreg - see comments]
- copy the .pfb files you downloaded from PCTeX here
- copy the .afm files you downloaded from PCTeX here
- copy the .tfm files from the tfm directory from the archive you downloaded from CTAN here
- copy the .vf files from the vf directory from the archive you downloaded from CTAN here
- copy the .map file from the archive you downloaded from CTAN here
- run latex on the .ins file from the archive you downloaded from CTAN; copy the resulting .sty file here
- run latex on the .dtx file from the archive you downloaded from CTAN; copy the resulting documentation here
- copy the source files you downloaded from CTAN and which don't go elsewhere (e.g. .dtx, .ins) here - this is entirely optional and is just for future reference; you can skip this step completely if you like
Now update TeX's file database by running
Now install the fonts for use by TeX by running
updmap-sys --enable Map mt11p.map.
You should now be able to use the fonts. Note that generating the documentation might fail if the documentation requires the fonts and the fonts are not yet installed. This won't stop the installation working but if you want the documentation, you can either just install the ready-made .pdf you downloaded as part of the CTAN archive or you can rerun latex on the .dtx file after installing the fonts.