The official website of the developer is down. Due to this, the PC Suite available for your device is no longer available to download. However, you can use the Software Informer website in order to find an application that can help you regarding the sync issue. I suggest you take a look at MoboRobo. This application is available for PC and Android. It's also compatible with most of the Android devices out there.
"I would like to use my mobile phone like a modem for PC to connect to the Internet". This can be done with the inbuilt features of your OS. You just need a USB cable to connect your phone to PC. After you do this, go to Menu of your device > Settings > Wireless and network > Tethering and portable hotspot > and activate USB tethering. By doing this, you can connect to the Internet with your PC through your mobile phone. If you don't have a USB cable, you can create a hotspot with your phone and connect to it with PC. The option is available in the same place as the one mentioned above.