Gears,Second gear misshifts when I drive, all other gears are fine.

Can the transmission be fixed when one of the gears (second gear, it's a manual car) does not properly work? I put the first gear it's fine, second gear I have to hold it firmly with my hand before switching to 3rd. So 1st, 3rd, 4th and 5th are fine, but 2nd gear I need to hold it otherwise it just comes out by itself whenever I push the gas pedal. It's like someone pushes it out with their hand every time I put it in second and give it gas while on the move. Will it get worse with time? How much approximately would it cost to fix it if at all possible?