Question: I'm planning on having overland trip in June starting from Turkey all the way home to Malaysia. So, I'm going to pass Iran Pakistan India Myanmar and Thailand before reaching my hometown.

Answer: The problem with your plan is that absolutely impossible to cross from India to Myanmar overland. So you might fly from India to Malaysia and use your 6 weeks in India and Iran. Or you can go from Kathmandu-Nepal via Tibet (China) to Laos and then to Thailand. This is the only overland way between India and Malaysia!
For your Iran visa fill in the visa form on http://www.uppersia.com/Iran-travel-services/iran-visa.html, it takes about 10 working days to get your reference number and two working days to collect your visa at the embassy by direct referral or one working week by posting the docs to the embassy. You can pay the visa fee in cash in Iran.
Check the cheapest Iran tours at http://www.uppersia.com/Iran-tours