Since you did not mention Bootcamp I'm assuming that you created a Virtual Disk base Virtual Machine with Fusion, is that correct?
If that is what you did, then here are my replies;
1) When I take back up of my mac with Time Machine, will it take back up of my windows7 data?
It will, but be aware that Time Machine is not really an appropriate means to back up Virtual Machines. The only Time Machine backups of a VM that are guaranteed to be valid / not-corrupted are ones that are taken when the VM is not running. By the time it finishes its' hourly backup on a running VM what it backed up first in the hour may have changed again and will not be consistent with the last bit of the virtual disk that it backs up. Windows may or may not be able to recover from such inconsistencies for any given backup.
Since Time Machine backs up roughly every hour you will end up with a lot of suspect backups in the course of a day. The other issue with Time Machine and any Virtual Machine backups is that the files that make up the Virtual Disk tend to be pretty large (either up to 2 GB per file for those split into 2 GB files, or the full size of the virtual disk for those not split). The way Time Machine works is that every time those Virtual Disk files change Time Machine will back the whole thing up. So let's say you run a non-split 40 Gig Virtual Machine for 8 hours and Time Machine is backing it up each hour. If the virtual machine is running something will have changed (minimum log files are getting written by Windows) in the virtual disk so it gets backed up each hour for a total of 320 GB, with a split virtual disk it would be some multiple of 2 GB per hour, still a lot.
2) If i restore my mac from Time Machine, Will it resotre my virtual PC (Windows7)?
Again, it will with the caveat that what it restores might be corrupted if the VM was running at the time of the backup.
3) How do I take back up my Windows7 from the mac?
My preference is to make a copy of the Virtual Machine when it is suspended or shut down (I typically make the backup copy with the VM shut down). I have found that doing this daily when I'm done with the VM gives me the level of protection that I need.
Depending on what you do with the VM some people store all of their data files on the Mac via shared folders and let Time Machine back up those data files. In either of these cases the VMs themselves are excluded from the Time Machine backups.
Good luck with whatever you decide to protect your data.
