mod

I want to create a mod LIKE HALFLIFE RPG! I want this:
I have a single map pack with 20 levels wich are big one map! Player walk throught the Big map and kill, collect, do missions, and on screen appears Player stats: health,exp,gold and other! I think there is needed a mysql and some scripting language, but how can i make this?
I can make the BIG level but how can i add stats, shop and other? Is there special file for this? And special fdg file for making maps!
The game will be like dragonfable or runescape etc.!

You will need to mod the HL1 engine to incorporate exp and currency. To do that you'll need to learn some programming (C++) to achieve the desired effects you wish and mod the engine, it can't be done in a map file alone. If you're up to the challenge you can check out the Valve Developer Wiki:

http://developer.valvesoftware.com/wiki/Main_Page

While mainly about the source engine, you can find some articles about the goldsrc engine.

Thanks! i'll be check out!