there is no argument, per se, that can *prove* the existence of god(s). there is no argument that can *disprove the existence of god(s). the evolution/creation debate is neither here nor there in the argument, since the scientific theory of evolution does not even touch on the topic of existence, or even original cause. it's a biological life theory. it is just a coincidence, that pretty much all atheists call upon the theory to explain diversity in nature, since it is the one that makes the most sense and is time tested. a fact, of sorts.
however, if you lack a belief in the existence of god(s), then you are in what philosophers and logicians call the default position. the neutral position. from there, evidence for the *positive* assertion (that god exists) must be forthcoming, and as we know, there really is none. you should be careful in asking people to prove a *negative* (non-existence of god), because that is essentially a waste of time, and fallacious. no one should ever ask you to prove to them that santa claus *does not* exist. the burden of proof does not rest on the unbeliever, but rather the believer, the one making the assertions for the positive. like carl sagan (an agnostic) said: "extraordinary claims require extraordinary evidence." the claim that a god exists is an extraordinary one indeed.
in instances like this, where a final conclusion cannot be obtained by pure proof alone, there are certain time tested tools that can help you determine if you want to stay in the default position or not. Occam's Razor is one. it simply states that in a situation like this, the argument that contains the fewest assumptions, should be the preferred one. the simplest explanation should be preferred. why? because pure proof is not forthcoming in deciding the HIGHEST LIKELIHOOD of truth. again, for emphasis: the highest likelihood of truth.
also, a tool of reason, that i quite like in this debate, is The God of the Gaps.