Then how did he get here, where did he come from? Your original purpose was to prove that god exists using the argument from design. This simply assumes a priori that he exists, and is thus the logical fallacy called begging the question, which is to assume the truth of what you're trying to prove. You've merely shifted the hypothesis from "Everything has a cause" to "Everything but god has a cause," which explains nothing, it's just a refusal to explain.
The fallacy of the false dichotomy. There are other options, and those are simply assumptions, not verifiable facts. You assume without justification that something must be eternal, a claim rooted in what I'm sure you'd agree are our limited human perceptions of what "eternal" actually means. Moreover, even if your assumption is correct, that something eternal caused the universe, that doesn't necessarily mean it was god. Maybe what's eternal is just geometry. Quarks, the simplest structures we know of, have three characteristics called colour, flavour, and charge, and they can't be pried apart. The three dimensions of space can't be pried apart either. So what's so great about 3 dimensions, as opposed to 2, or 4, or 24? Three dimensions, topologically, are what you need to make a knot that won't spontaneously unravel, and the simplest particles may be, according to some interpretations of string theory, knots in the fabric. That's pretty far out stuff, but at least it has some empirical grounding, unlike the claims for god's existence, and has some hope of leading to further insights.
Begging the question again, you try to prove he exists by assuming he exists.
The second postulate begs the question again, you assume the universe was designed in order to prove it was designed. You've offered that fallacy three times, first by assuming that god exists and the universe must therefore be designed, and here by assuming the universe is designed and therefore god must exist, and a third trivial time in between that follows from the first one. . Taken together, the argument is entirely circular: god exists because god exists,or alternatively, the universe is designed because the universe is designed. You've got nothing here but the same tired old fallacies I've seen many times before.
I was pretty sure you'd get to this "fine tuning" argument too, and I'm expecting the "irreducible complexity" argument eventually as well. With regard to the anthropic constants arguments you've offered, you need to understand two things. First, the composition of the atmosphere is not now what it's always been, so any argument based on its current composition, and its degree of transparency to certain wavelengths, as an example of design has no merit. The presence of free oxygen in particular is a consequence of the life on this planet, not a cause of it, and other forms of life have adapted to it. Second, numbers like the gravitational coupling constant are irrelevant, they depend entirely on the system of units chosen to express them in. The only things that matter from the fine tuning perspective are the dimensionless constants, numbers that'd be the same no matter what system of units was chosen, like the ratio between the proton and electron mass, or the relative strengths of the gravitational and electromagnetic forces.
So, how significant is this fine tuning? Several physicists have done some calculations on this, and their conclusion is, not very. I can give you citations if you wish, but in the meantime, this is the way it is: the requirement for stars long-lived and stable enough for life to develop on planets orbiting them is easily met with the critical parameters varying over ten orders of magnitude. There's nowhere near 100 critical parameters either, there are about two dozen, and for most purposes only 4 are necessary to define most properties of matter and energy: the masses of the electron and proton, and the relative strengths of the electromagnetic and nuclear strong interactions. Based on what we now call the Standard Model, the universe does not appear to be fine tuned for them.
