If you want the source of the syslog messages to be from your vlan1 192.168.1.2 address you can add the following line to your logging configuration on the 3750:
logging source-interface vlan 1
If you want the source of the syslog messages to be from your vlan1 192.168.1.2 address you can add the following line to your logging configuration on the 3750:
logging source-interface vlan 1