Hey Olix! Long time no see!
If you don't mind a bit of a learning curve, Blender has a video editor that should be capable of everything you need it to do. I haven't used it much myself, but it's been used in many professional production pipelines, so it should be fairly full-featured.
Here's a 23 minute tutorial about using Blender for video editing (aimed at new users):
http://processdiary.com/video-editing-i ... roduction/
Like the rest of Blender, it's designed around getting stuff done quickly rather than being super friendly to new users, but I reckon you could get the hang of it in an hour or so if you use the setup in that video tutorial. Basic stuff like inserting a video or audio file can be done by dragging the files onto the timeline, so it shouldn't be too bad. Have fun! If you've got any questions, I might be able to help.