you need a audio box. Something cheap like the maudio fastrack pro would do nicely, it's what I use. I'm sure others will come up with some other ideas. I really could do with decent monitors rather than decent computer speakers.
I use a Line6 Toneport and either mic my amp into it or use the models for scratch tracks. Works great with no latency that I can detect. I monitor with Sennheiser headphones or Behringer Truth powered monitors.
If you have Firewire in your laptop, I would look at the Presonus FireBox. It sounds better than most others in its class and has rock solid drivers.
There are a lot of options in monitors. Alesis and Behringer both make some decent sounding budget monitors. Just be sure you get something suitable for studio use. Your monitors are your lifeline when recording. The more accurate they are, the better.