You can use TeamViewer in both windows and linux. It will give you full control of the remote machine but I'm not sure if you can do file transfering...
For file transferring, connecting from windows to linux I would use winSCP, which access files through ssh, so you would have to install an run sshd on your linux box. If you haven't sshd in your ubuntu box, install it by doing $ sudo apt-get install ssh. You can start ssh daemon in ubuntu 11.10 with the command $ sudo service ssh start. From linux (Ubuntu 11.10) to windows (w7), I have successfully got into w7 machines in my local network by exploring the Network section in the left bar of the nautilus explorer. Sometimes, for some folders it would ask me for credentials to log into the remote machine, and file transferring was as simple as doing copy and paste (Ctrl+c, Ctrl+v)
hope to be helpful! good luck!