I will throw in some other options:
You can use any one of the free dynamic IP address DNS sites like noip.com and then there is no need to check if it changes.
For simple file transfers you can use winscp which is a windows SSH secure ftp client. This requires sshd to be configured on the linux PC and of course add a new user.
samba is not secure and I do not recommend allowing access outside of your local network. Instead you can setup a Virtual Private Network (VPN) like openswan, openvpn or poptop.