Out-of-Place Upgrade for 11.2.0.3 Question

 Hi Folks

I have windows 2008 r2 64-bit running oracle 11.2.0.2 rdbms 64-bit

i am looking at the install for 11.2.0.3 using out-of-place upgrade

what i do not understand is that if i install 11.2.0.3 in its own oracle home, how do i get all my windows services to point to the new 

11.2.0.3 home. do I have to manually redo them all ?

also what about all my listener.ora and tnsnames.ora files that have 11.2.0.2 in the first line of the files that are in the 11.2.0.2 home

is that also a manual change

how many other changes do i manually have to make ?

Thanks