The video tutorial you were following is for default skin, from what I can gather from your screenshot you are using this style :
https://vborg.vbsupport.ru/showthread.php?t=245708
You now need to check your stylevars to see if your main doc has changed in width, are you using fluid? fixed? Is your forum now at full 1280 width is the margins set to auto?
Once you have found this It will be easier to change your logo length to fit your forum size.
You are slso using a modification to change the way your notification looks, this should be asked in that particular forum.