need help finding a part for 40x

[scooterman27006]

i have a remington 40x that has taken up residence at my house but the fella that sold it to me - for whatever reason- used his pocket knife to show me that the small button/lever that you push to slide the bolt out sticks sometimes - well this time it didnt stick but he OMG broke it off right in front of my own eyes - my new baby and he broke it just like that - havent even paid him for it yet and well enough of that - i need to find this part - its the small button in the trigger gaurd that you push to allow the bolt to slide out - man is it smooth lol - anyhow i can get the bolt out without it but its got to be replaced - is it hard to replace this and should i take it to a gunsmith or is it something that i can just take the trigger assembly out and slide off and put the new one back in or much worse - i have found it kind of hard to find a parts place that has 40x listed for parts - any help appreciated - and oh yea i shot it 5 times at 100 yrds and yes its a keeper - he left without the gun