Replaced hard drive and restore disks don't work

I have a Toshiba L755 with Windows 7 Home Edition. My laptop starting telling me I am going to have a hard drive failure and I needed to back up files and replace the hard drive.
I bought a 640 GB hard drive off of ebay because they didn't have a 640 GB hard drive available through Toshiba. When we bought this laptop the hard drive size was a special feature at that time.
I installed the hard drive and then put the Toshiba restore disks in 1 - 4. When it gets finished with disk 4 it asks for the next disk. Can someone help me. I have called Toshiba support but have gotten no help.
I have read in different places you can clone the old hard drive and then put on the new hard drive but I am not sure how to do this.
Can someone help me. I want to get my computer back the way it used to be with the new hard drive.
Thanks in advance!