First of all, is that a weekly wage or a monthly wage? You cannot just divide by 4 to get the weekly figure from a monthly one, the Department will multiply a monthly wage by 12 and divide by 52 to get a weekly figure.
Also, is that a gross wage? For Jobseekers Allowance, they take the gross wage, minus PRSI, pension contributions and union dues.
Also, how many days in the week does your partner work? Is one of these days a Sunday?
I know that's all a bit complicated, but all those factors come into play. If you can set out all the above information, someone here would be able to let you know how this should have been assessed. If you are not happy with the assessment, you can always ask the deciding officer to review the decision, and you can also ask to receive the means assessment calculation if you haven't got it already.
As for a medical card, if your income has decreased then yes, you should apply again. If you have significant medical expenses, they can grant you a card even if you are above the limits if refusing you the card would cause you particular hardship.
Organisations like the irish national organisation of the unemployed or Citizens Information can go over the figures with you. The INOU run an information line on 01 8560088 or Citizens Information can be contacted on 1890 777 121