You can use the {TIME} token for this:
Say, '{TIME}'
The token will be replaced by the current time, according to your computer's internal clock(which should be synchronized to the internet) in a 24-hour format(use {time} if you want a 12-hour format instead).
For more information, have a look at VoiceAttackHelp.pdf(which you can open by pressing F1 while VoiceAttack has focus) page 128 to 131.