Preamble: I'm somewhat new to the workforce (only 2+ years worth of employment - with 1+ years being on my current position).
Context: I always have problems with salary negotiations and I always feel like I'm getting the low end of the deal.
I was offered a 1-year term position last November 2015 which got extended for another 6 months because they liked my work/output etc. When they took me in, both parties (employer and me) agreed that I will get the low end (down to the dollar) of the budget allotted for the position because I didn't have that much experience and the position isn't really a Junior position. They didn't want to over-compensate me if my lack of experience would become a problem later on.
Anyway, I'm getting close to the end of my term but my boss says she wants to offer me a permanent position. I think that would be the perfect time to re-negotiate my salary since they now have an idea of how I work and my output/result. My senior told me I exceeded their expectations because I finished all the work they intended me to finish during my term in like 5-6 months which resulted in more projects being assigned to me later on.
Long story short, once they offer me a permanent position I want to renegotiate my salary but I have no clue how to give an ideal range. I have a range in mind but I don't know if it's too narrow (giving the idea that I'm not too flexible with the amount) or too far apart (giving the idea that I have no clue as to what I should be compensated with and just giving random amounts).
Note
My question isn't about determining what I think I should be paid but more like how to provide a range. Would a range that has a difference of $5,000 be good? Something like that.