The specs are really close, I doubt you would be able to tell the difference between the two.
You didn't mention what version of windows your laptop is running and I can't tell for sure if the older model supports windows7.
OS support seems to be the deciding factor.
As for the two separate inpute channels, Radio Shack has a Y splitter that will take a mini-stereo in and send it out as two individual L & R out. Not much to worry about there.
If your laptop already has sound, however "bad" it might be, you might want to put the enseble together first and have it working before springing for the upgraded audio.
Oh.. and excuse me if I cut anyone off in the the queue