Most laptops use the same ATA-6 type interface in the 2.5" form factor. I did see some newer laptops with SATA hard drives but I'm sure your's is the regular type. The 1.8" drives are normally on Ultra-protable notebooks. Pretty much any ATA-6 2.5" notebook drive will fit.
By the way, I know they are more expensive but have you checked out the 7200RPM Travelstar drive by Hitachi? I heard 7200 rpm drives load a lot faster than 5400 rpm and way faster than 4200 rpm drives. They use about the same power (about 2.2 watts) as 5400 rpm drives so it shouldn't affect battery life too much. The only time it draws more power is when it spins up to speed but that's usually only when you turn on your computer and it only needs <4 seconds to start-up
You can get a USB adaptor for a notebook drive to "clone" the old hard drive onto your new one. Afterwards, you can put your old drive in the adaptor and use it as a USB storage device.
I copied the hard drive removal part from the repair manuel for you.