Macbook pro dual monitor

Hello, I am trying to hook up two monitors to my macbook pro. I am trying to hook up a dell 23 inch screen and my wacom cintiq tablet. I don't want to extend my screen simply just mirror the image. I got a dvi splitter cable and plugged everything in. My monitor seems to detect the connection but both the tablet and the screen aren't working. My macbook pro isn't showing them.

Here are my computers stats

Model Name: MacBook Pro
Model Identifier: MacBookPro5,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 3 MB
Memory: 4 GB

Any info on how I can fix this would be much appreciated!

Thanks

I suspect that the problem lies with the DVI splitter. Not sure any DVI splitter would work. I suspect what you need is something that behaves a bit more like a second graphics card. Something like the ATPM 15.08 - Review: OWC USB 2.0 Display Adapter might work. I would check with the company first though and get their thoughts.

Slydude is right, a splitter isn't going to solve your problem. I use a dualhead2go from Matrox to extend my MBP to 2 external monitors and it works great.