I have streamed from my wife's computer using home share in the past. Though I haven't tried it in the past few months. iTunes has become such a smoking pile of you know what that I refuse to use it anymore.
You could drag and drop the music files or copy/paste them to a micoSD card. I don't think you would be able to do it directly without some sort of remote access, like RDP. But I guess it might work over your network.
Why would you want to stream it anyway if the laptop would need to be there to do it? I must be missing something.
You can do it using Home Share, and with luck whatever you're using as a WiFi router may handle this fine -- but if it doesn't, it can be a time-dump trying to get it to work.
Your best bet is iTunes Match -- it's only $25 per year and provides a backup for your media library as well as commercial-free listening for iTunes Radio. You then have access to your library from anywhere your iPad has an internet connection, regardless of your SP...
It has built in memory management, downloads songs as you play them and keeps them around as long as there is space. iOS automatically dumps tracks that you've previously streamed/downloaded if space is need elsewhere.
That was why I suggested streaming from the cloud or using a micoSD card. You can pin whatever you want to the local system for off-line then delete it when finished. Can't beat free and simple either.
You can add up to 50,000 songs. I downloaded the app to my wife's computer. In the background it uploads songs to the Google cloud. As new music is added to iTunes it is synced to the cloud. The only negative that I found is that the DRM'd music that I purchased from iTunes years ago is not playable.