Configuration not clear and working fine

Hello, i like your plugin a lot, BUT i want to start with an amount of 10€ e.g. and have also the possibility to put 500 or more euro! With the logic from your plugin my maximum amount is only 20€ ,if i choose 10€ to start.
when i choose 250€ to start, the maximum amount is 500€ but the minimum is only 25€.
how can i config this in a better and more sense way?

Thanks for your reply,
could you give me a idea what to write there?
i would like start with 10 and at the end maybe 100 or if possible 500.

another question, i config the plugin at the plugin settings and integrated the plugin like this:
{jmb_donation paypal|example@googlemail.com|50|€}

but in the frontend it looks like this:

thanks, one more time where i found the jmb_donation.php ?
and is there a option to change the language? also when i click on donate it open a paypal site with english words, can i change this ?

Sorry this i dont understand exactly,
first i want to change the Donate Button (different language) and then after i click on it at the new window also from paypal.

Ok i found now, i just saw your links right now, sorry.
i changed at php form now this line:

<input type="hidden" name="cmd" value="_xclick" >

<input type="hidden" name="lc" value="de_DE" >

<input type="hidden" name="cmd" value="_xclick">
        <input type="hidden" name="lc" value="de_DE">