Your expenses are $260,000 plus $70,000 = $330,000
If selling it for $425,000 - your gain is $95,000.
If that is occasional sale - and you are not in business of flipping houses - the gain will be added to your other taxable income and you will pay income tax based on your total income, filing status, deduction, etc. - see tax rate schedule on last page in this publication - www.irs.gov/pub/irs-pdf/i1040tt.pdf
If you are single and that is your only income - your estimated federal income tax liability is $17,600.
If you held the property more than a year - the gain might be treated as long term capital gain taxable at reduced rate - not more than 15% - and your max tax would be $14,250
If you are in business of flipping houses - that income will be subject of self-employment taxes IN ADDITIONAL to income tax. The self-employment tax rate is 13.3% (for 2011) - so your estimated additional self-employment tax will be $12,635. In this case your total tax would be estimated as $17,600+$12,635=$30,000
Please be aware these are very raw estimates. To determine your exact tax liability, the tax return should be prepared.