Bootcamp update stopped at version 3.3
Depending on your Windows 7 (32bit/64bit) you may download - booted to Windows 7 - the Bootcamp drivers for Windows 7-32bit Boot Camp Support Software 4.0.4033 or Windows 7-64bit Boot Camp Support Software 5.1.5621 for your MacBook Pro Early 2011 directly.

Overview for all supported Mac models: System requirements to install Windows on your Mac using Boot Camp 

Unzip the downloaded file and start the setup.exe. Or update single drivers with the usual Windows methods.