There are lots of options, such as:
- Create a Linux VM using VirtualBox or similar. This is rather heavy really but works as you can share the drives
- Ext2fsd - Updated Nov 2017 for Ext3 (Ext4 work in progress). It is free
- DiskInternals Linux Reader - Not sure when this was last update but still seems current
- Ext2read - seems pretty dead but still works OK I think. You need to run this as an admin user
- Explore2fs - Not updated for a while and doesn't mention Windows 7 or 8 but I believe it does work at least on W7
- Paragon ExtFS - is still current and works on W8 too. Supports read and write and is free for personal use.