ooVoo should work fine but you do realize that with Virtual Box you
will still need a valid Windows COA and installation media ? Also the
Windows installation is just as vulnerable to viruses and malware as a
native Windows system would be so you'll need the same protection. The
advantage of Wine ( if the program works in it ) is that you get Linux
security so even programs that could get attacked in Windows are safe
to use.

BTW - if a Windows installation in Virtual Box does get hit by viruses
or malware it won't spread to Ubuntu, and there's a neat 'snapshot'
feature which you can use that can fully undo everything - like System
Restore on Speed Just need to take a snapshot once Windows is
configured but bear in mind this also includes data so going back also
means data loaded since then is toast.