Countries do not set limits on how much money you can carry. They just require you to declare the money as you leave and some countries require you to declare it when you enter, depending on how much you are carrying.
You can't do anything to speed up the process. You should have done your research before applying. Malaysia is one of the WORST places to apply for DTV. Multiple requests for information, often for the same information 2-3 times. Over a month is not unusual. And could still result in rejection.
You don't have any visa at all right now, so you cannot get "another visa."
You can go to your local immigration office and apply for a 30-day extension one time. Or if you want you can leave Thailand and return to get a new 60-day visa exempt stamp. Some Laos borders require you to stay in Laos 1-2 nights if you're trying to enter Thailand without a visa.
all wrong. You can't apply for an extension of DTV since you didn't enter on it. And the DTV extensions costing 10,000 was only a rumor and we know now it's the normal 1900 baht for an extension. But most immigration offices make it impossible to apply for DTV extensions so you're better off just leaving and returning every 6 months
you can apply in Thailand. But one of the requirements to apply is showing you have 800,000 baht in your Thai bank account. You cannot open a bank account as a tourist.