We'll need more info and perhaps some pics would help as well.
In my 81 Scamp
13 I have a T in the propane
line behind the refrigerator
to split off to refig and stove top.
Pretty easy to troubleshoot gas systems. Mix a cup of dishwashing detergent and water. Keep it on the soapy side and get a toothbrush. Turn the system on and starting at the tank soap all the connections. The leak will blow bubbles like a 3 year old.. Not a bad idea to take all your connections apart at this point, wrap new gas tape on, tighten them up and soap test.
Of course you'll need to terminate your stove line first and not really sure from your description what you need. To terminate a copper gas line you'll need a flair tool and the proper fixtures for the end. Flair tools are about $40 up. Simpler is to get the flexible gas line in the water heater section of hardware store and run a new piece from the T to the stove. They already have the terminations on both ends, just need to get the correct size.