go to the credit card forum, you're getting some mixed up info in here. as a general rule the most important figures for the bank/lender are:
1. your current income
2. debt to income ratio
Credit score is determined by a wide variety of factors
1. payment history - even if you're only charging $35 per month, paying it off and never missing a payment is crucial.
2. credit utilization, otherwise the percentage of available credit you are actually using
3. length of credit - how long have you had a credit history. are all of your credit accounts recent?
one thing to realize about credit score is that there are tradeoffs and most often, it will take time for certain things to positively affect your score. for instance, opening a new credit account will initially lower your score because of the hard inquiry and because it will show up as a new credit line (and if you have multiple new accounts within a short period of time that can have an even greater negative impact in the short term). BUT eventually it will help when you are able to show consecutive on time payments (payment history) AND because your credit utilization will go down.
with a 650 credit score, i think waiting a year is a good idea. it will also give you enough time to open another credit account. by the time you're ready to buy a home it will be a positive driver of your score. if you bank with Chase they have a free credit score monitoring function. most banks nowadays do.