it's not much, but i like it. anything that i should upgrade?

i don't know what kind of crank i have, but i will get a new one (recommendations please). the chain ring has 52 teeth and the cog is has 17. one more thing..i want to upgrade my bottom bracket, but don't know what kind. again, help please. thanks

by the way. i live in san jose (eastside area). let's ride fellow cyclists!