For your second problem, using a simple "start C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Chrome\Application\chrome.exe" should start the program and continue on with the batch. If not, you may want to check whether command extensions are enabled or disabled. If enabled, try to write the script to disable the extensions, then start the program, then re enable command extensions afterwards.
setlocal disableextensions
start C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Chrome\Application\chrome.exe
endlocal
To set a second IP, I need to ask if you are trying to set an IP for a seperate connection or if you are wanting the one "Local Area Connection" to have two IP addresses. If this is what you are wanting, how exactly are you setting it "manually?"