I am new to batch scripting. I need a complete batch script to find (set of given values) and replace them with new values in all the files in the folder and sub folder. Please help

The files might not be .txt always.
Sample file content:
./adt_btth/cfg/wf_btth.cfg:$BadFile_1=/atadata/ipm/adt_btth/badfiles/VSYM_PROD.bad
./adt_btth/cfg/wf_btth.cfg:$PMSessionLogFile=/export/home/ipm/adt_btth/logs/sessions/s_concate_usoc.log
(string in bold above needs to be replaced with new path.
New Value will look like:
./adt_btth/cfg/wf_btth.cfg:$BadFile_1=/Info_new/Info/NDW/badfiles/VSYM_PROD.bad
./adt_btth/cfg/wf_btth.cfg:$PMSessionLogFile=/home/logs/info/NDW/logs/sessions/s_concate_usoc.log
There will be many such lines in one file and then many files in a folder and subfolders.
Please help. Please let me know if i should give more information here.