My advice is skip the sidearm for now and put that extra $270 into your main gun. If you've got your heart set on a sidearm and a 1911 (I don't blame you, very nice gun) then don't go with WE, their guns in general and the 1911 in particular are plagued with problems. You want full metal, try KJW (you can get one for about $300 BNIB once you're av'ed). If full metal isn't a requirement then WA or TM is the way to go.
As for your main, if you like the MP5 then Classic Army (lots of full metal goodness) is the way to go, though you'd be hard pressed to get one for $500. You could probably manage a stock or nearly stock TM for that price. But the MP5 suffers enough against full size rifles without running stock. It really needs some upgrades, especially the TM's which tend to fire relatively cool stock. Of course if you went midgrade rather then highgrade then you could get an MP5 with some decent upgrades for that price. ICS or G&G aren't too expensive even upgraded some.
But really, if you can afford it, then highgrade is the way to go, especially for your first gun. So get the sidearm further down the road and put your all towards a highgrade gun right off the hop.