Splitter definitely wouldn't do it -
You need the equivalent of two separate HDMI outputs.
Can't attest to the quality, but something like this might work for you:
http://www.bestbuy.com/site/j5-create-superspeed-usb-3-0-to-2-x-hdmi-external-video-adapter-silver-white/5615018.p?skuId=5615018 If your laptop already has one HDMI output, you could send that output to one monitor, and use a single-output USB to HDMI adapter for the second.
Some laptop hardware manufacturers offer docking stations with dual monitor outputs; might be worth looking in to.
FWIW -
Adding a USB video adapter might be asking a lot for you laptop if you're already driving a USB audio interface and other hardware like MIDI controllers. As much as a like having two big monitors for my desktop, I have found that just adding one bigger monitor to my laptop (I use a 23" with mine, attached directly to the laptop HDMI output, when I'm hanging out at my "2nd home") makes a world of difference. I setup the HDMI monitor directly behind and above the laptop, and use the monitor for all the detail work, while using the laptop screen for the console, VST's etc.
Works great!