Do you charge hourly or by the job?

Both. It depends on the job 

Are you available to complete my job this week?

Most likely no.  However, if it's an emergency or something small I may be able to squeeze it in.  If your job can wait, I'd like to set up a time to look at the work needed. Then I will create a proposal for you to review, and we can set up a time for me to complete the work.