The first thing you need to do is meet with a lender. They will go over your details and let you know what you qualify for. It is important to have someone you trust. Ask around friends, family, co-workers. If you cannot find one, I know of several that are trustworthy.
Then you need talk with a reputable real estate agent. Go through the same process as above for lender. If you do not know of one, I would be happy to help.
Specifically, if you need to sell your current home, you will want to get that on the market. There are not many sellers that will accept an offer with a home sale contingency if your home is not yet on the market. If you need to find that value of your current home, you can either get an appraiser which you will have to pay for or you can ask a real estate agent to perform a comparable market analysis for you, (CMA).
Once you find an agent, he/she should be able to guide you through the process.
Hope this helps.
Your first step would be to talk to aloan officer from a mortgage company to see what you can qualify for. They might be able to take some of your savings to payoff your bills to raise your credit score. Also they will determine if you can purchase without the sale of your home. IF you need to sell your home before you can purchase then you'll need to find out what amount you'll need from the sale of your home from you lender. I have many lenders names I can email you if you'd like. Then you need to talk to a realtor to help you with the sale of your home. I can perform a market analysis to help determine your list price. Let me know if you need help with the purchase of another home as well.
Whatever your needs are, I'd be happy to help.
The first thing you are going to want to do is meet with a Mortgage Professional. They will be able to go over your credit issues and help you be on the right path to improving your credit issues. The other thing you will have to deal with is that it looks like you are planning on putting about a 5% down payment on a Jumbo size loan. Plus they will have to take in account your debt ratios, you are buying a 600,000 home and you make less than 200,000 a year. You may be very tight on your qualifying rations depending on what your current debt is, the amount home owners insurance will be, and what property taxes will be.
Meet with a Mortgage Professional ASAP
My advice would be to find a lender with whom you would get a loan pre-approval. Ask your friends and colleagues if they can recommend someone directly, but if not, you can use online forums like Trulia to begin the conversation.
A pre-approval is simply an analysis of income, assets and credit and it's going to tell you what you can and cannot do. Either way, you make progress and can adjust your plans accordingly.
If I can help, let me know. I do have contacts in WI who could assist.