If you're assuming your wife will get a new job soon, why not wait? What difference will a few months make? Plus, it'll insure that you wont end up paying a mortgage on only your income should she have difficulty finding something new that suits her (added bonus: she wont feel pressured to take something she isn't thrilled about).
When considering financial commitments that project beyond a year, best to get your ducks in a row first. Just one man's opinion...
Why I don't want to wait: The market is at the bottom right now.
Oh my goodness.

I mean this with all do respect, but I strongly recommend you think long and hard and research before you act. What do you base your market analysis on? I follow the markets real estate and otherwise as closely as the celtics, the nba or other hobies and I can assure you... the market is at bottom right now has been the mantra since the spring of 2006. My humble opinion is that you are 100% false on your market analysis. I'm also very conscerned for you and your families future when I read that you are looking into buying a 300k home on a 45k salary. This is 100% impossible. Even with your wifes income it is financial suicide, and your wife's income is not reliable, obviously. I'm not passing judgment, my wife also has undocumented income. She runs a legal in home daycare, but clients come and go, I don't count on that cash for my mortgage.
Your plan is reckless, and it is not uncommon. Frankly, this line of thinking and decision making is why we are in this crisis. Banks may share the blame, depending on your political views. The bank handed me the rope to hang myself with in the spring of 2007. I chose to purchase a home for 88k less than what I was approved for. Like so many reckless Americans I had the cash in hand (figuratively speaking), I had the wife demanding 4 bedrooms, granite counter tops, acres of land, the best school systems money can buy, picket fences etc etc etc.
I had the discipline to resist the temptation to act irresponsibly. Now I have a mortgage I can comfortably afford.
Most importantly though Jsaad, unlike so many other Americans, I still have my home. What good would that granite counter top and 4th bedroom been if I had no wife and kids to share it with? It is the mans responsibility to be the captain and guide the ship, if the ship sinks into financial ruin, you could be the only one left on board brotha.
I mean this with the utmost respect, I just want you to have some perspective and a healthy dose of caution for the path ahead.
best of luck.
oh and one more thing, I could write a 30 page thesis on why this market is NOT at the bottom. Your patience will be rewarded I can assure you! I have the means to upgrade considerably right now. I increased my salary a year ago by 45% and I have flawless credit, I remain in my humble home to this day. There is no rush brotha.
If I'm wrong about the market continuing down i can certainly assure you that it will not spike dramatically anyway. You won't miss anything. It will be a u shaped reconvery or a slight annual increase at best.
but i'm telling you, for a gazzillion reasons this market is not done it's decline.