Run netstat -f in a batch file for a specific amount of time then quit and move on to the next command in the batch file?
i would say use multiple scripts for that.
what i mean is get the parameters you need in a separate script and output it into a .log file or such.
then in the main script read the .log file and if the info inside it is satisfactory then close the script, move on to the next step.
like you said you need to read an output anyway so make it into a log file and that would solve the timeout you need.
in case you want to double check if the parameter in the netstat is still the one you want just copy the comand to run the script and read the output again after some steps