These are all my time (GMT).
Today I'm on from now until 9pm, but revising for my biology exam tomorrow mainly
Tomorrow I should be on from 6:30pm-9pm, on Friday I may be going out, if I do then I won't be on at all, if I don't then 4pm-10pm, Saturday, same case as friday, but 1pm-4pm and 7pm-9:30pm. Sunday: prety much all day.
Just say which of those fits your schedule best, and I can usually bend the times by around 15 mins each way.