I am assuming that at 4.5% this is an adjustable loan. I don't know of anyone writing 30 year fixed loans that low. If so, you also need to figure what your payment might be down the road.
Also, are you planning on a down payment? Typically all advertised rates are for 20% down. If you are putting less than that down, the rates will be higher. Either by paying a mortgage insurance premium, or a second mortgage to make up the difference.
As far as property taxes, Tony is right, it varies quite a bit throughout the nation. For example, in San Diego County 1.2% of the assesed value is normal. But in Texas, I understand that 2.4% is normal.
Homeowners insurance can vary also depending upon location, price, etc. Typically between $400 to $800 a year.
Taxes and Insurance can be impounded into an escrow account which would be paid monthly with your mortgage, or you can pay them on your own, just be prepaired for some big bills throughout the year.
Tony, or his wife, is absolutely correcet. Credit and income play a big part in which loan you can qualify for.
Find a reputable mortgage broker in your area and explain your situation. If he won't talk to you without filling out a credit application, then find someone that will.
Good luck.