1. If you can/know to navigate to C:\Windows\System32 in Finder you can do the same for C:\Documents and Settings\<username>\Application Data\ and copy your files from there, you should see a "Documents and Settings" folder like you see a "Windows" folder when you open the disk in OS X and then navigate the same way as you did for System32.
2. You simply copy the files to a 'safe' place via Mac, like you copy any other file under OS X, the contents of the files will remain intact and unaltered on the OS X side.
3. Here's an article of the steps you can follow to recover Windows from the dll problem:
http://pcsupport.about.com/od/findbyerrormessage/a/msvcrt-dll-not-found-missing-error.htm
3. However, you likely need to use step 10 of the previous article, as the ones before probably will not work from what you have said. In that case the correct way to solve this problem in Windows is via a Repair Install, this requires a that you have the Windows XP CD (preferably with SP3), if this is a Bootcamp install it also should be done while booting natively, this procedure is almost like installing a fresh copy of Windows except your files, settings and programs will remain intact. This will require that you re-download and reinstall all updates via Windows Update, might require some drivers to to reinstalled, and Parallels Tools also.
http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm
4.
[Dangerous, proceed with caution] Finally, it's possible to replace the file in Windows by having read and write access to the Windows volume, you can do that by using OSXFUSE (more on that later), but
you really have to be sure that you know what you are doing, meaning,
that the file you'll be putting there is the one that's right for the system, the
correct version of it, that you don't delete or modify any other file inside the Volume.
Read this first:
http://pcsupport.about.com/od/findtheproblem/qt/dll-download.htm
OS X FUSE:
http://osxfuse.github.io/
NTFS 3G of Mac OS X (this is what will give you read and write access to Windows):
https://github.com/osxfuse/osxfuse/wiki/NTFS-3GClick to expand...