A tig machine is likely the worst possible choice you could make at this juncture. You are a novice welder, and TIG is a somewhat advanced skill.
SO lets solve your MIG issue before throwing you into the pit of boiling oil which is what tig would be like initially.
First off I would post a picture of what you are trying to weld, along with what machine you are using, what gas is in your bottle (just post what it says on the label), what CFM your gas is flowing at, and what you are welding, what wire is in your machine (again, just post the label details eg; er70s-6, etc), and what settings you are using.
I have a feeling that you are either trying to weld thin galvanized sheet, or possibly aluminum. First see if a magnet sticks to it, a picture should show the rest.