You should still be able to obtain an expansion around such an arbitrary c but I really advice you to rephrase your problem, perhaps start by replacing c with x and call this function f(x), consider the Taylor series expansion of the function f(x) around a constant c where c>=1)! Maybe the assumption that c>=1 is probably to put a constraint on your choice of p so that the result is always real or take sure the f is infinitely differentiable!!
To evaluate Taylor Series, follow the Taylor series "equation" by taking the first, second, third and fourth, ... derivatives of f(x) with respect to x, take each derivative and when you're done replace x with the constant c, and multiply each i'th derivative by (x-c)^(i)/(factorial(i))!
What you have now is a Taylor series expansion of of the function f(x) around a constant c>=1, x appears as a variable, c only as a constant, as well as p of course!