Searching for text and making modification

[HotLanta]

In another thread recently I had asked for help with a macro that will loop through a folder containing text files and add information from my Excel form into each text file.
I'm working on that project still and I have another question:

The software that creates the text files only exports the time as HH:MM and either AM or PM. Additionally it adds a $$ double dollar sign to the line.
Specifically in the text file it looks like this:

$$ Time: 12:15 PM

The software that I am importing the text files into 1) Cannot read lines that begin with $$ and 2) needs the time to be in HH:MM:SS format.

I should say that the second software uses HH:MM:SS as a serial number for the data.
I say that to say it really doesn't matter to me that I don't know the actual SS from the export software. I just need the SS to be unique for each file though.

My thought was, can we

Loop through a folder of text files
Look for the $$ Time: 12:15 PM
Delete the $$
Delete AM or PM
To 12:15 add :01
Loop through the text files and add 01 to each time?

Maybe it will look like this:

12:15:01
12:15:02
12:15:03
12:16:01
12:16:02
12:17:01

Another option - could we look for $$ Time: 12:15 PM, delete that line, and replace it with the =NOW() computer time in HH:MM:SS format?

Thank you