There is a bulk effects move function under the tools menu - where you can move all effects between time x and y by an offset z. You would want to reimport the audio first, don't modify the sequence length initially but you can do that when have moved your effects into position. This is easier than cut/paste since effects can often be hidden lots of levels down, depending on how complex your display/node configuration is.
There is also a function to move timing marks (right click on the mark group names). They have slightly different dialogs but can be used to achieve exactly the same thing. If you have effects and timing marks, you will likely want to bring both forwards by the same time interval.