Actually, the correct adverb here is always 'seriously' as you are using it to qualify the verb 'take', so if I was talking about my job, I would say "I take my job seriously". If I am talking about my sister, I would say "I wish my sister would take me seriously". The only time to use the adverb 'serious' is when talking about something you wish to describe as having the atribute of seriousness – for instance, this is a serious post.
Remember, when you are qualifying a verb, you need to use an adverb, when you are describing an attribute, you need to use the adjective. However, in some slang speech, particularly in North America, you will often hear the incorrect use such as 'I wish you would take me serious'. There is also a form which is a little slangy, but is correct – you can say "Are you serious?" Which is a slangy form of "Do you mean what you are saying".