1 No evidence can show any effect of computer to the baby. But I think you'd better avoid using computers.
2 No evidence shows any effect of coffeein(?) to the baby. Actually I did see a Chinese book say green tea is good to pregnancy. But I suggest you stop drinking tea now. There is coffeein-free tea in market, but it doesn't taste good.
3 You should have more milk, fruit, vegitable if you can.
BTW I suggest you see a doctor ASAP. She/he will give advice on almost everything, from daily food to sex.