Top Bar is a little more tricky unfortunately as it sets the height to 100% (of the bar) and the width to auto. If you apply just a max-width to this then it will distort you logo (as it will still be stuck at 100% high)
You will therefore need to force the height back to auto (to preserve the aspect ratio). This will mean that the logo no longer fills the height of the bar and so you will either need to add some padding to the top of the image to vertically centralise it or in some cases it may be possible to alter the height of the bar to coincide with the aspect ratio of your image.
Here it is with some padding - play around with the width to get it the size you want and then adjust the padding until it is vertically centred.
@media screen and (max-width: 640px){
.top-bar .name img{
max-width: 120px;
height: auto!important;
padding-top:8px
}
}