your stats is really good, but your LUC is a bit low. try to push it up till you have 500+
then you can critic all the time, which will help you more
but at lvl53, you can wear a full legend or goddess ( or mixed ) dragon set.
try to aim for 600 LUC, 300DEX and 300+ STR.
if having issues to reach the above goals, >500 luc with 250+ dex will work too. if you have 200 STR ( or less due of not have money for lvl6's ) you can consider to use a high attack bow ( read with +STR/+assault and enchant )
my UM was 650 LUC, 450 DEX and 400 STR with ~900 attack and it did good at yellow mobs.