CSS Change for mobile device (extending page fields on my account page)

Hi
I need some help resolving this issue on the "My Account" page. currently when the page is smaller or when viewing on mobile devices the fields where user can enter their information are also reduced. can this be increased and extended to the blue line on the right in the screenshot ?
Also can the current balance result be moved onto the same line as the text "My current credit balance:" ?
also if possible to move the username / other field names to the left slightly to align to the left blue line - see screenshot ?

Please see Screenshot: http://monosnap.com/image/6i3XjNRtulbCnFKHG2ImtkkhHYAnMj

Domain Link: http://tinyurl.com/nepl4y9

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Thanks
Tom