But I cannot download any packages because the Internet configuration is not detecting my Realtek Wireless card
A couple of suggestions (assuming you can borrow an Internet connection):
1. Use the forum search on "realtek" and see if there are any helpful threads.
2. load the pci-utils and/or usb-utils extensions, look through "lspci" or "lsusb" and paste the line about your realtek hardware in this thread