4k60 over Thunderbolt 1?
Your MacBook Pro model came with either an AMD Radeon HD 6490M or 6750M and Intel HD Graphics 3000 as its graphics card options.

While your MBP does support up to two Thunderbolt displays in the following modes: dual display extended and video mirroring, it's only capable of an external resolution of up to 2560x1600 pixels.

Unfortunately, this resolution output falls below 4K resolution which is basically in the order of 4000x2000 pixels.

However, the maximum resolution of your 15.4" built in display is 1680x1050 pixels, so while you can't output 4K resolution to an  external display, the 2560x1600 pixels you can output is still an improvement.