2001 Honda Accord

I have a 2001 Honda Accord it has 185,000 roughly
and it needs a oil change. I just replaced the water
pump timing belt. I as other I see did not know that
the type of coolant would effect it I used the green
coolant and when I took it to the shop they said that
it had started to mess up the water pump and made
it leak. So to try and prevent any further damage to
my car. What type of oil should be used when doing
an at home oil change, which is best to help my car
last longer. It says that it takes 5w30. Are there
different brands of that if so which is best and
where do I get it. Thank you to all for the help.