You will need to file for guardianship using the procedures set out in Chapter 10 of Title 37.2 of the Virginia Code:
http://leg1.state.va.us/cgi-bin/legp504.exe?000+cod+TOC37020000010000000000000
I strongly recommend that you seek the services of an attorney. This is fairly complicated, and,a small technical error can bring your case to an early end.