You have 2 options:
Option 1.
Just add negative margin to the sidebar CSS like this:
@media screen and (min-width: 48em){
#secondary{
margin-right:-150px;
}
}
Option 2.
Add more max-width to the wrapper:
@media screen and (min-width: 48em){
.wrap{
max-width: 1340px;//the default is 1000
padding-left: 348px;//you have to add padding left so the left side doesnt move, the amount needs to be proportional to the amount of max-width you are incrementing
}
}
i added the media query, its needed so this CSS doesnt affect the mobile view.