There is a very nice free music notation software that i have been using for some time now.
It will allow you to put guitar fingerings for RH and LH that Tuxguitar may not be able to do at the moment.
Google for 'musescore' and you should be able to find the website and program to download. I recommend this very highly.
Here are some features of the program
MuseScore is a free cross platform WYSIWYG music notation program, licenced under GNU GPL.
WYSIWYG (What you see is what you get), notes are entered on a "virtual note sheet"
Unlimited number of staves
Up to four voices per staff - I use this feature to separate the bass, harmony and melody lines especially for solo guitar pieces - Tux guitar at the moment only allow 2 voices per staff
Easy and fast note entry with mouse, keyboard or MIDI
Build in Menus for RH and LH fingering. Powerful page layout features enable you to arrange the printout of your pieces
in anyway you like.
You can add in graphics, lyrics to the score.
Integrated sequencer and FluidSynth software synthesizer
Import and export of MusicXML and Standard MIDI Files
Available for Windows, Mac and Linux
Translated in 26 languages
GNU GPL licenced
Best of all for me it can print directly to pdf format which make it very easy for me to arrange pieces etc for the students which i am coaching.
*note: i am just a satisfied user of the above program and in no way associated in the design, programing etc of musescore.