Wazifa to fall pregnant

Q: My question is regarding my sister. She got married two and a half years ago and is eager to have a baby. Allah Ta'ala has not blessed them with a child regarding that she is depressed is there any dua to conceive please pray for my sister.

Intending talaaq by saying "ab khatam"

Q: My husband gave me divorce in 2 sms's within half hour intervals on the 21st of September. Then after 1 month he made but without any guilt. He continuously makes threats. I agreed to go but couldn't go back as in the last moment I talked to him and he quarrelled again. So on the 17th of December he used the word aab khatam and said he signed the paper. But still I didn't get the paper. Is divorce complete should I sit in iddat?

Buying an item on terms for a fixed price

Q: I want to buy furniture for my house as I am shifting to a new flat. But I can't really pay cash currently. But the shopkeeper is charging interest on that. So is it permissible? I have heard that if I know the total increased price then it is permissible. e.g If I buy a car now I have to pay 8000 but on instalments the new price will be 10,000. But they increase it and say that its the interest rate. However I know the final price so is it permissible?