Why would you have problems with Serial.write() and Serial.read() ?
what you should perhaps do is have sortof the following:
readBal = Serial.read();
The while loop would keep the code in that position until a value has been received, also perhaps note what values have been sent as it could be sent as ASCII and not as just the number so you might need to subtract "0" from it....
I have recantly found the read String on the web but havent tried it out yet as the above would only read one character so you might need to string them together to receive multiple characters...
Hope this helps at all