So why the big deal about having to be in 'C', then?

If it really must be 'C', then you're going to have to get down and learn it anyway - so surely now is the best time to start?!

What I said before does still apply: if we just spoon-feed you some 'C' code, you will learn very little.

You say you already know assembler, so this should be just a matter of the language - you're not also trying to understand program construction, the 8051, etc,...

I suggest you get yourself a Copy of The 'C' Programming Languge, by Kernighan & Ritchie.

Maybe also download the free Keil evaluation;
Read the uVision Getting Started guide, and work through the example projects in it.

Without a firm foundation, your project is doomed to collapse...