Network Adapter Drivers for Windows 7* and Windows Server 2008 R2, x64 editions* is what you are asking for. However, I am not sure that a driver update will resolve your issue. You might need to change one of the power saving options in the network connection's properties or modify your BIOS settings. Try community searches on "sleep", "resume", and "wake" to see what other users have tried. You might be able to solve your issue with one of the suggestions found in the searches.
Please post back here when you find out what resolved the issue. Good luck.
Did the not connecting after wake up issue start after upgrading the driver from the driver that Windows 7 installed? You might want to try rolling back your driver to an earlier version. There is also an earlier driver (dated 06/05/2009, version 18.104.22.168) that came with the version 14.5 software package that you could try. That driver is newer than the one supplied with Windows, but it is older than the newest driver (dated 09/01/2009, version 22.214.171.124) that is in the version 14.7 software package I linked to in my first reply.
If you have the issue no matter which driver you use, you might need to contact technical support for your computer (or motherboard if you built your own computer) to get help with a resolution.
One other idea that might (or might not) help, is to try different power management settings in the properties for your network connection.
I hope this helps.