a few ways to fix your chainline so that you could use the outer ring would be to:
-get a shorter or adjustable bottom bracket that would bring your driveside crankarm in a bit (you will have to check to see if yor chainrings will clear your chainstay)
-run your big chainring on the inside of the spider (would require new chainring bolts and would still depend on if your frame has clearance to run that big of a ring on the inside
-respace the rear hub so that the cog lines up better with the bigger chainring and then redish the wheel so that the rim is centered (not super hard, but more involved than a new BB or new cog/chainring)

i have no experience with spacers for the cog so i'll leave that to someone else

42/17 is a more normal gear ratio than 52/17 for most people, especially beginners. i'd suggest keeping it like you have it for a while. If you feel like your are spinning too much, you can get a smaller cog (14,15,16) or a mid size ring (44-49).