You have to have patience when solo mining... Instead of getting constant shares all the time you will now be getting blocks several times a day. From my experience, at this difficulty and your 7500Kh/s hash rate, you should have gotten around 3 blocks in the last 12 hours if you are set up correctly with the stock Spreadcoin miner...

But be aware, it isn't consistent like clockwork, I have gone 7 hours without seeing a single block only to have 5 of them pop up in the next 2 hours... It's all about long term average.

Hope that helps!  

And here's a GPU miner for the NVIDIA crew. Compute 3.0 support should be easy enough, but for now it's 3.5/5.0/5.2 only.

Win32 binary: https://github.com/tsiv/spreadminer/releases
Source: https://github.com/tsiv/spreadminer