upgrading the laptop

Hello, everyone. 
 
Well, it so happens that i have about $550 to buy a better laptop.  it has to be a laptop because i store the laptop in a different place where i record music.  because i travel with it i want it to be light, so i'm inclined to 13" ones.  (live in the city, no car) i'm also inclined that it's Windows 7, 'cause there seems that there not that many sound cards, printers, etc. for Windows 8.  the amount of laptops out makes choosing overwhelming.  i recently learned about the features to look in a laptop, like memory, harddrive, processor...  i know the brands Dell and HP of laptops i've had in the past, but i haven't found anything i really want in those brands.  i don't know the other brands well.  any comments that may lead me in the right direction will be greatly appreciated.
 
i'll consider new, gently used, and manufactured refurbished.  i won't consider bidding for it on ebay or any other bidding website.  (don't have the patience for that!)
 
when i get the new laptop i will install MC6 in it, an join the MC in 21st century.
 
Thanks,
sirena del mar