I'm wandering whether the following use case diagram is correct because I'm not sure if such notations are possible: something is going from extending use case, and this notation of this transition. I haven't found any information regarding such cases and would be glad if someone could help me.
To express that a (partial or secondary) use case is used only under certain cercumstances and you want to express them explicitly, you can use extension points. An extension points defines explicitly the conditions when the Main use case is extended. In reality, this Feature of uml is Quitte rarely used. Because it adds a high degree of concreteness to the abstrakt Level of use cases.
In your example you are using the wrong kind of relation. You are showing an extend relation, which expressed that a Stereotype can be applied to a meta type. Instead you should use an extends relation, which has a dashed line and on open arrow head.